diff --git a/mysql-test/include/check_shared_row_lock.inc b/mysql-test/include/check_shared_row_lock.inc
index efc7e13b3aa..1c9d9b0c3c6 100644
--- a/mysql-test/include/check_shared_row_lock.inc
+++ b/mysql-test/include/check_shared_row_lock.inc
@@ -33,7 +33,8 @@ connection default;
 # least it acquires S-locks on some of rows.
 let $wait_condition=
   select count(*) = 1 from information_schema.processlist
-  where state in ("Sending data","statistics", "preparing") and
+  where state in ("Sending data","statistics", "preparing", "updating",
+                  "executing", "Searching rows for update") and
         info = "$wait_statement";
 --source include/wait_condition.inc
 
diff --git a/mysql-test/include/subselect_mat_cost.inc b/mysql-test/include/subselect_mat_cost.inc
new file mode 100644
index 00000000000..04b116e9527
--- /dev/null
+++ b/mysql-test/include/subselect_mat_cost.inc
@@ -0,0 +1,152 @@
+-- echo
+-- echo /* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+-- echo
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+-- echo
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+
+-- echo
+-- echo /*
+-- echo   B. "Natural" examples of subqueries without grouping that
+-- echo   cannot be flattened into semijoin.
+-- echo */
+
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+-- echo
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+-- echo UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+-- echo
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+-- echo
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+
+-- echo
+-- echo /* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+-- echo
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+-- echo
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+-- echo
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+-- echo
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+-- echo
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+
+-- echo
+-- echo /*
+-- echo   D. Subqueries for which materialization is not possible, and the
+-- echo   optimizer reverts to in-to-exists.
+-- echo */
+# The first two cases are rejected during the prepare phase by the procedure
+# subquery_types_allow_materialization().
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+-- echo
+# The following two subqueries return the result of a string function with a
+# blob argument, where the return type may be != blob. These are rejected during
+# cost-based optimization when attempting to create a temporary table.
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+-- echo
+
+
+-- echo
+-- echo /* E. Edge cases. */
+-- echo
+
+-- echo /* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+--error ER_ILLEGAL_SUBQUERY_OPTIMIZER_SWITCHES
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+set @@optimizer_switch = @save_optimizer_switch;
+
+-- echo /* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+
+-- echo /* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+-- echo UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+
+-- echo /* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+
+-- echo /* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+-- echo TODO this test produces wrong result due to missing logic to handle the case
+-- echo when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+select a1 from t1 where a1 in (select max(b1) from t2);
+-- echo
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+
+-- echo /* E.6 make_join_select detects impossible WHERE. *
+
+-- echo TODO
+
+-- echo /* E.7 constant optimization detects "no matching row in const table". */
+
+-- echo TODO
+
+-- echo /* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+
+-- echo
+-- echo /* F. UPDATE/DELETE with subqueries. */
+-- echo
+
+-- echo TODO
+-- echo
diff --git a/mysql-test/r/explain.result b/mysql-test/r/explain.result
index 25fc524bc9b..75f05478c82 100644
--- a/mysql-test/r/explain.result
+++ b/mysql-test/r/explain.result
@@ -262,7 +262,7 @@ WHERE 1 > ALL((SELECT 1 FROM t1 JOIN t1 a ON (MATCH(t1.f1) AGAINST (""))
 WHERE t1.f1 GROUP BY t1.f1));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	
-2	SUBQUERY	a	system	NULL	NULL	NULL	NULL	1	Using filesort
+2	SUBQUERY	a	system	NULL	NULL	NULL	NULL	1	
 2	SUBQUERY	t1	fulltext	f1	f1	0		1	Using where
 PREPARE stmt FROM
 'EXPLAIN SELECT 1 FROM t1
diff --git a/mysql-test/r/func_compress.result b/mysql-test/r/func_compress.result
index b4e61d0e4fc..5c87939c75b 100644
--- a/mysql-test/r/func_compress.result
+++ b/mysql-test/r/func_compress.result
@@ -102,6 +102,8 @@ a
 foo
 Warnings:
 Error	1259	ZLIB: Input data corrupted
+Error	1259	ZLIB: Input data corrupted
+Error	1259	ZLIB: Input data corrupted
 explain select *, uncompress(a) from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	
diff --git a/mysql-test/r/func_group.result b/mysql-test/r/func_group.result
index 4a1c375ea5f..27474278f05 100644
--- a/mysql-test/r/func_group.result
+++ b/mysql-test/r/func_group.result
@@ -1755,6 +1755,8 @@ CREATE TABLE empty1 (a int);
 INSERT INTO t1 VALUES (1,'c'),(2,NULL);
 INSERT INTO t2 VALUES (3,'m'),(4,NULL);
 INSERT INTO t3 VALUES (1,'n');
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 
 #
 # 1) Test that subquery materialization is setup for query with
@@ -1812,10 +1814,6 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 # 3) Test that subquery materialization is setup for query with
 #    premature optimize() exit due to "Select tables optimized away"
 #
-# NOTE: The result of this query is actually wrong; it should be NULL
-# See BUG#47762. Even so, the test case is still needed to test
-# that the HAVING subquery does not crash the server
-# 
 SELECT MIN(pk)
 FROM t1
 WHERE pk=NULL
@@ -1882,8 +1880,10 @@ HAVING ('m') IN (
 SELECT v
 FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	t1	index	NULL	PRIMARY	4	NULL	2	Using where; Using index
 3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+set @@optimizer_switch=@save_optimizer_switch;
 #
 # Cleanup for BUG#46680
 #
diff --git a/mysql-test/r/group_by.result b/mysql-test/r/group_by.result
index f22a8b0fb55..54c8999adca 100644
--- a/mysql-test/r/group_by.result
+++ b/mysql-test/r/group_by.result
@@ -1543,8 +1543,7 @@ EXPLAIN SELECT 1 FROM t1 WHERE a IN
 (SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	index	PRIMARY,i2	PRIMARY	4	NULL	144	Using index
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	4	func	1	
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	144	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	144	Using where; FirstMatch(t1)
 CREATE TABLE t2 (a INT, b INT, KEY(a));
 INSERT INTO t2 VALUES (1, 1), (2, 2), (3,3), (4,4);
 EXPLAIN SELECT a, SUM(b) FROM t2 GROUP BY a LIMIT 2;
diff --git a/mysql-test/r/group_min_max.result b/mysql-test/r/group_min_max.result
index 974521ec120..20b0c054480 100644
--- a/mysql-test/r/group_min_max.result
+++ b/mysql-test/r/group_min_max.result
@@ -1360,12 +1360,158 @@ group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	index	NULL	idx_t1_1	163	NULL	128	Using where; Using index
 2	DEPENDENT SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
+select a1,a2,b,min(c),max(c) from t1
+where exists ( select * from t2 where t2.c = t1.c )
+group by a1,a2,b;
+a1	a2	b	min(c)	max(c)
+a	a	a	a111	d111
+a	a	b	e112	h112
+a	b	a	i121	l121
+a	b	b	m122	p122
+b	a	a	a211	d211
+b	a	b	e212	h212
+b	b	a	i221	l221
+b	b	b	m222	p222
+c	a	a	a311	d311
+c	a	b	e312	h312
+c	b	a	i321	l321
+c	b	b	m322	p322
+d	a	a	a411	d411
+d	a	b	e412	h412
+d	b	a	i421	l421
+d	b	b	m422	p422
 explain select a1,a2,b,min(c),max(c) from t1
 where exists ( select * from t2 where t2.c > 'b1' )
 group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	range	NULL	idx_t1_1	147	NULL	17	Using index for group-by
+1	PRIMARY	t1	range	NULL	idx_t1_1	147	NULL	17	Using where; Using index for group-by
 2	SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
+select a1,a2,b,min(c),max(c) from t1
+where exists ( select * from t2 where t2.c > 'b1' )
+group by a1,a2,b;
+a1	a2	b	min(c)	max(c)
+a	a	a	a111	d111
+a	a	b	e112	h112
+a	b	a	i121	l121
+a	b	b	m122	p122
+b	a	a	a211	d211
+b	a	b	e212	h212
+b	b	a	i221	l221
+b	b	b	m222	p222
+c	a	a	a311	d311
+c	a	b	e312	h312
+c	b	a	i321	l321
+c	b	b	m322	p322
+d	a	a	a411	d411
+d	a	b	e412	h412
+d	b	a	i421	l421
+d	b	b	m422	p422
+explain select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2 where t1.b > 'a' and t2.c > 'b1' )
+group by a1,a2,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	range	NULL	idx_t1_1	147	NULL	17	Using where; Using index for group-by
+2	DEPENDENT SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
+select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2 where t1.b > 'a' and t2.c > 'b1' )
+group by a1,a2,b;
+a1	a2	b	c	min(c)	max(c)
+a	a	b	h112	e112	h112
+a	b	b	p122	m122	p122
+b	a	b	h212	e212	h212
+b	b	b	p222	m222	p222
+c	a	b	h312	e312	h312
+c	b	b	p322	m322	p322
+d	a	b	h412	e412	h412
+d	b	b	p422	m422	p422
+explain select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2
+where t2.c in (select c from t3 where t3.c > t1.b) and
+t2.c > 'b1' )
+group by a1,a2,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	range	NULL	idx_t1_1	147	NULL	17	Using where; Using index for group-by
+2	DEPENDENT SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
+2	DEPENDENT SUBQUERY	t3	index	NULL	idx_t3_1	10	NULL	192	Using where; Using index; FirstMatch(t2)
+select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2
+where t2.c in (select c from t3 where t3.c > t1.b) and
+t2.c > 'b1' )
+group by a1,a2,b;
+a1	a2	b	c	min(c)	max(c)
+a	a	a	d111	a111	d111
+a	a	b	h112	e112	h112
+a	b	a	l121	i121	l121
+a	b	b	p122	m122	p122
+b	a	a	d211	a211	d211
+b	a	b	h212	e212	h212
+b	b	a	l221	i221	l221
+b	b	b	p222	m222	p222
+c	a	a	d311	a311	d311
+c	a	b	h312	e312	h312
+c	b	a	l321	i321	l321
+c	b	b	p322	m322	p322
+d	a	a	d411	a411	d411
+d	a	b	h412	e412	h412
+d	b	a	l421	i421	l421
+d	b	b	p422	m422	p422
+explain select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2 where t1.c > 'a' and t2.c > 'b1' )
+group by a1,a2,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	idx_t1_1	163	NULL	128	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
+select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2 where t1.c > 'a' and t2.c > 'b1' )
+group by a1,a2,b;
+a1	a2	b	c	min(c)	max(c)
+a	a	a	a111	a111	d111
+a	a	b	e112	e112	h112
+a	b	a	i121	i121	l121
+a	b	b	m122	m122	p122
+b	a	a	a211	a211	d211
+b	a	b	e212	e212	h212
+b	b	a	i221	i221	l221
+b	b	b	m222	m222	p222
+c	a	a	a311	a311	d311
+c	a	b	e312	e312	h312
+c	b	a	i321	i321	l321
+c	b	b	m322	m322	p322
+d	a	a	a411	a411	d411
+d	a	b	e412	e412	h412
+d	b	a	i421	i421	l421
+d	b	b	m422	m422	p422
+explain select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2
+where t2.c in (select c from t3 where t3.c > t1.c) and
+t2.c > 'b1' )
+group by a1,a2,b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	idx_t1_1	163	NULL	128	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
+2	DEPENDENT SUBQUERY	t3	index	NULL	idx_t3_1	10	NULL	192	Using where; Using index; FirstMatch(t2)
+select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2
+where t2.c in (select c from t3 where t3.c > t1.c) and
+t2.c > 'b1' )
+group by a1,a2,b;
+a1	a2	b	c	min(c)	max(c)
+a	a	a	a111	a111	d111
+a	a	b	e112	e112	h112
+a	b	a	i121	i121	l121
+a	b	b	m122	m122	p122
+b	a	a	a211	a211	d211
+b	a	b	e212	e212	h212
+b	b	a	i221	i221	l221
+b	b	b	m222	m222	p222
+c	a	a	a311	a311	d311
+c	a	b	e312	e312	h312
+c	b	a	i321	i321	l321
+c	b	b	m322	m322	o322
+d	a	a	a411	a411	d411
+d	a	b	e412	e412	h412
+d	b	a	i421	i421	l421
+d	b	b	m422	m422	o422
 explain select a1,a2,b,min(c),max(c) from t1 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	idx_t1_0,idx_t1_1,idx_t1_2	idx_t1_1	147	NULL	17	Using where; Using index for group-by
@@ -2246,17 +2392,17 @@ EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE EXISTS
 (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using index
-2	SUBQUERY	t1	index	NULL	a	10	NULL	15	Using index
+2	SUBQUERY	t1	index	NULL	a	10	NULL	1	Using index
 EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
 (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using index
 2	SUBQUERY	t1	range	NULL	a	5	NULL	8	Using index for group-by
 EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
 a IN (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using where; Using index
-2	SUBQUERY	t1	range	NULL	a	5	NULL	8	Using index for group-by
+2	DEPENDENT SUBQUERY	t1	index	NULL	a	10	NULL	1	Using index
 EXPLAIN SELECT 1 FROM t1 AS t1_outer GROUP BY a HAVING 
 a > (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
diff --git a/mysql-test/r/index_merge_myisam.result b/mysql-test/r/index_merge_myisam.result
index 4871f42cffc..83edf674f81 100644
--- a/mysql-test/r/index_merge_myisam.result
+++ b/mysql-test/r/index_merge_myisam.result
@@ -1484,7 +1484,7 @@ EXPLAIN SELECT t1.f1 FROM t1
 WHERE (SELECT COUNT(*) FROM t2 WHERE t2.f3 = 'h' AND t2.f2 = t1.f1) = 0 AND t1.f1 = 2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	system	PRIMARY	NULL	NULL	NULL	1	
-2	DEPENDENT SUBQUERY	t2	ref	f2,f3	f2	5		1	Using where
+2	DEPENDENT SUBQUERY	t2	ref	f2,f3	f2	5	const	1	Using where
 DROP TABLE t1,t2;
 create table t0 (a int);
 insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
diff --git a/mysql-test/r/join.result b/mysql-test/r/join.result
index 935e3ee3b62..e3ef617503f 100644
--- a/mysql-test/r/join.result
+++ b/mysql-test/r/join.result
@@ -1314,7 +1314,7 @@ WHERE t1.f1 IN (SELECT f1 FROM t1) AND t1.f1 = t2.f1 OR t1.f1 = 9;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	2	Using where
 1	PRIMARY	t2	ALL	PRIMARY	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
-2	SUBQUERY	t1	index	NULL	PRIMARY	4	NULL	2	Using index
+2	DEPENDENT SUBQUERY	t1	unique_subquery	PRIMARY	PRIMARY	4	func	1	Using index
 SELECT STRAIGHT_JOIN * FROM t1 JOIN t2 ON t2.f2 = t1.f1
 WHERE t1.f1 IN (SELECT f1 FROM t1) AND t1.f1 = t2.f1 OR t1.f1 = 9;
 f1	f2	f1	f2
diff --git a/mysql-test/r/join_nested.result b/mysql-test/r/join_nested.result
index 9d60059ac28..3dc6a6338cb 100644
--- a/mysql-test/r/join_nested.result
+++ b/mysql-test/r/join_nested.result
@@ -854,7 +854,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	ref	idx_b	idx_b	5	test.t3.b	2	100.00	Using where
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b` from `test`.`t3` join `test`.`t4` left join (`test`.`t1` join `test`.`t2`) on((((`test`.`t3`.`a` = 1) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`b`))) and (`test`.`t3`.`b` is not null))) where 1
+Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b` from `test`.`t3` join `test`.`t4` left join (`test`.`t1` join `test`.`t2`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t3`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`b`) and (`test`.`t3`.`b` is not null))) where 1
 SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
 FROM (t3,t4)
 LEFT JOIN              
@@ -966,7 +966,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 CREATE INDEX idx_b ON t8(b);
 EXPLAIN EXTENDED
 SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
@@ -1015,7 +1015,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	ref	idx_b	idx_b	5	test.t5.b	2	100.00	Using where
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 CREATE INDEX idx_b ON t1(b);
 CREATE INDEX idx_a ON t0(a);
 EXPLAIN EXTENDED
@@ -1065,7 +1065,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	ref	idx_b	idx_b	5	test.t5.b	2	100.00	Using where
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
 t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
 FROM t0,t1
diff --git a/mysql-test/r/join_nested_jcl6.result b/mysql-test/r/join_nested_jcl6.result
index 3345540af96..26c0a9cadfe 100644
--- a/mysql-test/r/join_nested_jcl6.result
+++ b/mysql-test/r/join_nested_jcl6.result
@@ -239,7 +239,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	3	100.00	Using join buffer (flat, BNL join)
 1	SIMPLE	t8	hash_ALL	NULL	#hash#$hj	5	test.t7.b	2	100.00	Using where; Using join buffer (incremental, BNLH join)
 Warnings:
-Note	1003	select `test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b` from `test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and (`test`.`t8`.`b` = `test`.`t7`.`b`)) and (`test`.`t7`.`b` is not null))) where 1
+Note	1003	select `test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b` from `test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t8`.`b` = `test`.`t7`.`b`) and (`test`.`t7`.`b` is not null))) where 1
 SELECT t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
 FROM (t6, t7)
 LEFT JOIN 
@@ -560,7 +560,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (incremental, BNL join)
 1	SIMPLE	t8	hash_ALL	NULL	#hash#$hj	5	test.t5.b	2	100.00	Using where; Using join buffer (incremental, BNLH join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) where ((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) where ((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)))
 SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
 t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
 FROM t0,t1
@@ -656,7 +656,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	hash_ALL	NULL	#hash#$hj	5	test.t5.b	2	100.00	Using where; Using join buffer (incremental, BNLH join)
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (incremental, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 SELECT t9.a,t9.b
 FROM t9;
 a	b
@@ -847,7 +847,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using join buffer (incremental, BNL join)
 1	SIMPLE	t4	hash_ALL	NULL	#hash#$hj	5	test.t2.b	2	100.00	Using where; Using join buffer (incremental, BNLH join)
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b` from `test`.`t1` join `test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) where (`test`.`t1`.`a` <= 2)
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b` from `test`.`t1` join `test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) where (`test`.`t1`.`a` <= 2)
 CREATE INDEX idx_b ON t2(b);
 EXPLAIN EXTENDED
 SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
@@ -861,7 +861,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	ref	idx_b	idx_b	5	test.t3.b	2	100.00	Using where; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using join buffer (incremental, BNL join)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b` from `test`.`t3` join `test`.`t4` left join (`test`.`t1` join `test`.`t2`) on((((`test`.`t3`.`a` = 1) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`b`))) and (`test`.`t3`.`b` is not null))) where 1
+Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b` from `test`.`t3` join `test`.`t4` left join (`test`.`t1` join `test`.`t2`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t3`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`b`) and (`test`.`t3`.`b` is not null))) where 1
 SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
 FROM (t3,t4)
 LEFT JOIN              
@@ -923,7 +923,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	hash_ALL	NULL	#hash#$hj	5	test.t5.b	2	100.00	Using where; Using join buffer (incremental, BNLH join)
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (incremental, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 CREATE INDEX idx_b ON t4(b);
 CREATE INDEX idx_b ON t5(b);
 EXPLAIN EXTENDED
@@ -973,7 +973,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	hash_ALL	NULL	#hash#$hj	5	test.t5.b	2	100.00	Using where; Using join buffer (incremental, BNLH join)
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (incremental, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 CREATE INDEX idx_b ON t8(b);
 EXPLAIN EXTENDED
 SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
@@ -1022,7 +1022,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	ref	idx_b	idx_b	5	test.t5.b	2	100.00	Using where; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (incremental, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 CREATE INDEX idx_b ON t1(b);
 CREATE INDEX idx_a ON t0(a);
 EXPLAIN EXTENDED
@@ -1072,7 +1072,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	ref	idx_b	idx_b	5	test.t7.b	2	100.00	Using where; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (incremental, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on((((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))) and (`test`.`t7`.`b` is not null)))) on((((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`) and (`test`.`t7`.`b` is not null)))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t5`.`b` is not null)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
 t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
 FROM t0,t1
diff --git a/mysql-test/r/key.result b/mysql-test/r/key.result
index fcc09a0244d..46313411e7d 100644
--- a/mysql-test/r/key.result
+++ b/mysql-test/r/key.result
@@ -598,7 +598,7 @@ VALUES
 EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
 (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using index
 2	SUBQUERY	t1	range	NULL	a	5	NULL	8	Using index for group-by
 SELECT 1 as RES FROM t1 AS t1_outer WHERE 
 (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
diff --git a/mysql-test/r/myisam_mrr.result b/mysql-test/r/myisam_mrr.result
index 2f1560ea981..38e1841dd41 100644
--- a/mysql-test/r/myisam_mrr.result
+++ b/mysql-test/r/myisam_mrr.result
@@ -347,10 +347,10 @@ WHERE t2.int_key IS NULL
 GROUP BY t2.pk
 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
-2	SUBQUERY	t2	ref	int_key	int_key	5		1	100.00	Using index condition; Using where; Using filesort
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+2	SUBQUERY	t2	ref	int_key	int_key	5	const	1	100.00	Using index condition; Using where; Using filesort
 Warnings:
-Note	1003	select min(`test`.`t1`.`pk`) AS `MIN(t1.pk)` from `test`.`t1` where 0
+Note	1003	select min(`test`.`t1`.`pk`) AS `MIN(t1.pk)` from `test`.`t1` where exists(select `test`.`t2`.`pk` from `test`.`t2` where isnull(`test`.`t2`.`int_key`) group by `test`.`t2`.`pk`)
 DROP TABLE t1, t2;
 #
 # BUG#42048 Discrepancy between MyISAM and Maria's ICP implementation
diff --git a/mysql-test/r/optimizer_switch.result b/mysql-test/r/optimizer_switch.result
index 0ae1d54fc7a..9d90aba3fb2 100644
--- a/mysql-test/r/optimizer_switch.result
+++ b/mysql-test/r/optimizer_switch.result
@@ -4,19 +4,19 @@
 #
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='index_merge=off,index_merge_union=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='index_merge_union=on';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,index_merge_sort_union=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch=4;
 ERROR 42000: Variable 'optimizer_switch' can't be set to the value of '4'
 set optimizer_switch=NULL;
@@ -43,60 +43,60 @@ set optimizer_switch=default;
 set optimizer_switch='index_merge=off,index_merge_union=off,default';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch=default;
 select @@global.optimizer_switch;
 @@global.optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set @@global.optimizer_switch=default;
 select @@global.optimizer_switch;
 @@global.optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 #
 # Check index_merge's @@optimizer_switch flags
 #
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 
 BUG#37120 optimizer_switch allowable values not according to specification
 
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,materialization=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,semijoin=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,loosescan=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=off,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=off,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,semijoin=off,materialization=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,materialization=off,semijoin=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,semijoin=off,materialization=off,loosescan=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=off,materialization=off,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,semijoin=off,loosescan=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=off,materialization=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch='default,materialization=off,loosescan=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=off,materialization=off,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=off,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
 set optimizer_switch=default;
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr_sort_keys=on,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on
diff --git a/mysql-test/r/ps_11bugs.result b/mysql-test/r/ps_11bugs.result
index 5c11163ab9e..f9f0525646d 100644
--- a/mysql-test/r/ps_11bugs.result
+++ b/mysql-test/r/ps_11bugs.result
@@ -120,9 +120,9 @@ create table t1 (a int primary key);
 insert into t1 values (1);
 explain select * from t1 where 3 in (select (1+1) union select 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING
-3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
 select * from t1 where 3 in (select (1+1) union select 1);
 a
diff --git a/mysql-test/r/strict.result b/mysql-test/r/strict.result
index 241f4198bf7..999d273186f 100644
--- a/mysql-test/r/strict.result
+++ b/mysql-test/r/strict.result
@@ -1105,8 +1105,6 @@ count(*)
 7
 Warnings:
 Error	1411	Incorrect datetime value: '2004.12.12 10:22:61' for function str_to_date
-Error	1411	Incorrect datetime value: '2004.12.12 10:22:61' for function str_to_date
-Error	1411	Incorrect datetime value: '2004.12.12 10:22:61' for function str_to_date
 drop table t1;
 create table t1 (col1 char(3), col2 integer);
 insert into t1 (col1) values (cast(1000 as char(3)));
diff --git a/mysql-test/r/subselect.result b/mysql-test/r/subselect.result
index 53f38141f66..b57cdb16562 100644
--- a/mysql-test/r/subselect.result
+++ b/mysql-test/r/subselect.result
@@ -423,7 +423,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where 1
+Note	1003	select 1 AS `1` from `test`.`t1` where (1 = (select 1 union select 1))
 drop table t1;
 CREATE TABLE `t1` (
 `numeropost` mediumint(8) unsigned NOT NULL auto_increment,
@@ -909,7 +909,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref_or_null	a	a	5	func	2	100.00	Using where; Using index
 2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
+Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`a` from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
 drop table t1,t2,t3;
 create table t1 (a float);
 select 10.5 IN (SELECT * from t1 LIMIT 1);
@@ -1180,9 +1180,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)
@@ -1190,9 +1190,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 drop table t1;
 CREATE TABLE `t1` (
 `i` int(11) NOT NULL default '0',
@@ -1535,34 +1535,34 @@ select * from t3 where NULL >= any (select b from t2);
 a
 explain extended select * from t3 where NULL >= any (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(NULL) from `test`.`t2`)))
 select * from t3 where NULL >= any (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= any (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select NULL from `test`.`t2` group by 1)))
 select * from t3 where NULL >= some (select b from t2);
 a
 explain extended select * from t3 where NULL >= some (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(NULL) from `test`.`t2`)))
 select * from t3 where NULL >= some (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= some (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select NULL from `test`.`t2` group by 1)))
 insert into t2 values (2,2), (2,1), (3,3), (3,1);
 select * from t3 where a > all (select max(b) from t2 group by a);
 a
@@ -1571,7 +1571,7 @@ a
 explain extended select * from t3 where a > all (select max(b) from t2 group by a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary
 Warnings:
 Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <not>((`test`.`t3`.`a` <= <max>(select max(`test`.`t2`.`b`) from `test`.`t2` group by `test`.`t2`.`a`)))
 drop table t2, t3;
@@ -1624,7 +1624,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 'e' AS `s1` from `test`.`t1` where 1
+Note	1003	select 'e' AS `s1` from `test`.`t1` where <nop>(('f' > <min>(select 'e' from `test`.`t1` union select 'e' from `test`.`t1`)))
 drop table t1;
 CREATE TABLE t1 (number char(11) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1;
 INSERT INTO t1 VALUES ('69294728265'),('18621828126'),('89356874041'),('95895001874');
@@ -2831,14 +2831,13 @@ Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cac
 explain extended SELECT one,two from t1 where ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = 'N');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	10	func	1	1.00	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; FirstMatch(t1)
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`flag` = 'N'))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`two` = `test`.`t1`.`two`) and (`test`.`t2`.`one` = `test`.`t1`.`one`) and (`test`.`t2`.`flag` = 'N'))
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cache><`test`.`t1`.`two`,`test`.`t1`.`one`>(<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one`,`test`.`t2`.`two` from `test`.`t2` where (`test`.`t2`.`flag` = '0') group by `test`.`t2`.`one`,`test`.`t2`.`two` having (trigcond(((<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) or isnull(`test`.`t2`.`one`))) and trigcond(((<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`) or isnull(`test`.`t2`.`two`))) and trigcond(<is_not_null_test>(`test`.`t2`.`one`)) and trigcond(<is_not_null_test>(`test`.`t2`.`two`)))))) AS `test` from `test`.`t1`
 DROP TABLE t1,t2;
@@ -3110,10 +3109,10 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
-4
 1
+2
 3
+4
 SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
 (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b));
@@ -3122,8 +3121,8 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
 1
+2
 3
 4
 SELECT a FROM t1
@@ -3420,7 +3419,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 ALTER TABLE t1 ADD INDEX(a);
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 a	b
@@ -3431,7 +3430,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	
 DROP TABLE t1;
 create table t1( f1 int,f2 int);
 insert into t1 values (1,1),(2,2);
@@ -4320,16 +4319,16 @@ CREATE TABLE t1 (a INT);
 INSERT INTO t1 VALUES (1),(2);
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,1 in ( <materialize> (select 1 from `test`.`t1` group by `test`.`t1`.`a` ), <primary_index_lookup>(1 in <temporary table> on distinct_key where ((1 = `materialized subselect`.`1`))))))
+Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having (<cache>(1) = <ref_null_helper>(1)))))
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 WHERE a > 3 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary; Using filesort
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,1 in ( <materialize> (select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` ), <primary_index_lookup>(1 in <temporary table> on distinct_key where ((1 = `materialized subselect`.`1`))))))
+Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having (<cache>(1) = <ref_null_helper>(1)))))
 DROP TABLE t1;
 #
 # Bug#45061: Incorrectly market field caused wrong result.
@@ -5012,11 +5011,10 @@ explain SELECT * FROM ot1,ot4
 WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
 FROM it2,it3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	24	
-1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
-2	SUBQUERY	it2	ALL	NULL	NULL	NULL	NULL	4	
-2	SUBQUERY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	Start temporary
+1	PRIMARY	it2	ALL	NULL	NULL	NULL	NULL	4	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
+1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; End temporary; Using join buffer (flat, BNL join)
 DROP TABLE IF EXISTS ot1, ot4, it2, it3;
 #
 # Bug#729039: NULL keys used to evaluate subquery
diff --git a/mysql-test/r/subselect3.result b/mysql-test/r/subselect3.result
index 3d7cbdd9ff7..166014c005d 100644
--- a/mysql-test/r/subselect3.result
+++ b/mysql-test/r/subselect3.result
@@ -28,7 +28,7 @@ select a, oref, a in (select max(ie)
 from t1 where oref=t2.oref group by grp) Z from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary
 Warnings:
 Note	1276	Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref`,<expr_cache><`test`.`t2`.`a`,`test`.`t2`.`oref`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select max(`test`.`t1`.`ie`) from `test`.`t1` where (`test`.`t1`.`oref` = `test`.`t2`.`oref`) group by `test`.`t1`.`grp` having trigcond((<cache>(`test`.`t2`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`))))))) AS `Z` from `test`.`t2`
@@ -37,7 +37,7 @@ select a, oref from t2
 where a in (select max(ie) from t1 where oref=t2.oref group by grp);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary
 Warnings:
 Note	1276	Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`,`test`.`t2`.`oref`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select max(`test`.`t1`.`ie`) from `test`.`t1` where (`test`.`t1`.`oref` = `test`.`t2`.`oref`) group by `test`.`t1`.`grp` having (<cache>(`test`.`t2`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`))))))
@@ -69,7 +69,7 @@ set @@optimizer_switch="partial_match_rowid_merge=off,partial_match_table_scan=o
 explain extended select a in (select max(ie) from t1 where oref=4 group by grp) from t3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select <expr_cache><`test`.`t3`.`a`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select max(`test`.`t1`.`ie`) from `test`.`t1` where (`test`.`t1`.`oref` = 4) group by `test`.`t1`.`grp` having trigcond((<cache>(`test`.`t3`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`))))))) AS `a in (select max(ie) from t1 where oref=4 group by grp)` from `test`.`t3`
 set @@optimizer_switch=@save_optimizer_switch;
@@ -121,7 +121,7 @@ Handler_read_key	0
 Handler_read_next	0
 Handler_read_prev	0
 Handler_read_rnd	0
-Handler_read_rnd_next	29
+Handler_read_rnd_next	35
 select 'No key lookups, seq reads: 29= 5 reads from t2 + 4 * 6 reads from t1.' Z;
 Z
 No key lookups, seq reads: 29= 5 reads from t2 + 4 * 6 reads from t1.
@@ -163,7 +163,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref	a	a	5	test.t1.b	1	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t3.oref' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select 1 from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond(((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`)))) having trigcond(<is_not_null_test>(`test`.`t1`.`a`))))) AS `Z` from `test`.`t3`
+Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond(((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`))) and (`test`.`t2`.`a` = `test`.`t1`.`b`)) having trigcond(<is_not_null_test>(`test`.`t1`.`a`))))) AS `Z` from `test`.`t3`
 drop table t1, t2, t3;
 create table t1 (a int NOT NULL, b int NOT NULL, key(a));
 insert into t1 values 
@@ -191,7 +191,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref	a	a	4	test.t1.b	1	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t3.oref' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select 1 from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`)))))) AS `Z` from `test`.`t3`
+Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`)) and (`test`.`t2`.`a` = `test`.`t1`.`b`))))) AS `Z` from `test`.`t3`
 drop table t1,t2,t3;
 create table t1 (oref int, grp int);
 insert into t1 (oref, grp) values
@@ -212,7 +212,7 @@ select a, oref,
 a in (select count(*) from t1 group by grp having grp=t2.oref) Z from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
 Note	1276	Field or reference 't2.oref' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref`,<expr_cache><`test`.`t2`.`a`,`test`.`t2`.`oref`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select count(0) from `test`.`t1` group by `test`.`t1`.`grp` having ((`test`.`t1`.`grp` = `test`.`t2`.`oref`) and trigcond((<cache>(`test`.`t2`.`a`) = <ref_null_helper>(count(0)))))))) AS `Z` from `test`.`t2`
@@ -463,7 +463,7 @@ group by grp having min(ie) > 1) Z
 from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	7	
-2	DEPENDENT SUBQUERY	t1	ref	idx	idx	5	test.t2.oref	2	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ref	idx	idx	5	test.t2.oref	2	Using where; Using temporary
 select oref, a, 
 a in (select min(ie) from t1 where oref=t2.oref 
 group by grp having min(ie) > 1) Z 
@@ -624,7 +624,7 @@ explain
 select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp) Z from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	7	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	Using where; Using temporary
 select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp) Z from t2;
 oref	a	Z
 ee	NULL	0
@@ -711,7 +711,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	100.00	Using index
 2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t1`.`a`) and (not(<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t1` where ((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`)) having <is_not_null_test>(`test`.`t1`.`a`)))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t1`.`a`) and (not(<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` where trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`))) having trigcond(<is_not_null_test>(`test`.`t1`.`a`))))))))
 SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1));
 a
 SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1 WHERE a > 4));
@@ -732,7 +732,7 @@ WHERE t3.name='xxx' AND t2.id=t3.id);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
 2	DEPENDENT SUBQUERY	t2	eq_ref	PRIMARY	PRIMARY	4	func	1	Using where; Using index; Full scan on NULL key
-2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	func	1	Using index condition; Using where; Full scan on NULL key
+2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.id	1	Using where
 SELECT * FROM t1
 WHERE t1.id NOT IN (SELECT t2.id FROM t2,t3 
 WHERE t3.name='xxx' AND t2.id=t3.id);
@@ -841,11 +841,16 @@ x	ROW(11, 12) = (SELECT MAX(x), 22)	ROW(11, 12) IN (SELECT MAX(x), 22)
 1	0	0
 2	0	0
 11	0	0
-# 2nd and 3rd columns should be same for x == 11 only
+# 2nd and 3rd columns should be same
+EXPLAIN SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 12), ROW(11, 12) IN (SELECT MAX(x), 12) FROM t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 12), ROW(11, 12) IN (SELECT MAX(x), 12) FROM t1;
 x	ROW(11, 12) = (SELECT MAX(x), 12)	ROW(11, 12) IN (SELECT MAX(x), 12)
-1	0	1
-2	0	1
+1	0	0
+2	0	0
 11	1	1
 DROP TABLE t1;
 # both columns should be same
@@ -971,7 +976,7 @@ i1	i2
 # Baseline:
 SHOW STATUS LIKE '%Handler_read_rnd_next';
 Variable_name	Value
-Handler_read_rnd_next	18
+Handler_read_rnd_next	17
 
 INSERT INTO t1 VALUES (NULL, NULL);
 FLUSH STATUS;
@@ -988,7 +993,7 @@ i1	i2
 # (read record from t1, but do not read from t2)
 SHOW STATUS LIKE '%Handler_read_rnd_next';
 Variable_name	Value
-Handler_read_rnd_next	19
+Handler_read_rnd_next	18
 set @@optimizer_switch=@save_optimizer_switch2;
 DROP TABLE t1,t2;
 End of 5.1 tests
@@ -1023,11 +1028,10 @@ update t22 set c = '2005-12-08 15:58:27' where a = 255;
 explain select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	8	Using temporary; Using filesort
+1	PRIMARY	t11	ALL	NULL	NULL	NULL	NULL	8	Using where; Using temporary; Using filesort; Start temporary
+1	PRIMARY	t12	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	t22	ALL	NULL	NULL	NULL	NULL	26	Using where; End temporary; Using join buffer (flat, BNL join)
 1	PRIMARY	t21	ALL	NULL	NULL	NULL	NULL	26	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	t22	ALL	NULL	NULL	NULL	NULL	26	Using where; Using join buffer (flat, BNL join)
-2	SUBQUERY	t11	ALL	NULL	NULL	NULL	NULL	8	Using where
-2	SUBQUERY	t12	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
 select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 a	b	c
@@ -1040,9 +1044,8 @@ explain
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	X	ALL	NULL	NULL	NULL	NULL	2	
-2	DEPENDENT SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	subselect3	eq_ref	unique_key	unique_key	5	func	1	
-3	SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	2	
+2	DEPENDENT SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+2	DEPENDENT SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 subq
 NULL
@@ -1112,8 +1115,7 @@ set @@optimizer_switch=@save_optimizer_switch;
 explain select * from (select a from t0) X where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	11	
-1	PRIMARY	subselect3	eq_ref	unique_key	unique_key	5	func	1	
-3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	20	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where; FirstMatch(<derived2>)
 2	DERIVED	t0	ALL	NULL	NULL	NULL	NULL	11	
 drop table t0, t1;
 create table t0 (a int);
@@ -1125,18 +1127,16 @@ create table t3 (a int);
 insert into t3 select A.a + 10*B.a from t0 A, t0 B;
 explain select * from t3 where a in (select kp1 from t1 where kp1<20);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	range	kp1	kp1	5	NULL	48	Using where; Using index
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	Using where
+1	PRIMARY	t1	ref	kp1	kp1	5	test.t3.a	1	Using index; FirstMatch(t3)
 create table t4 (pk int primary key);
 insert into t4 select a from t3;
 explain select * from t3 where a in (select t1.kp1 from t1,t4 where kp1<20
 and t4.pk=t1.c);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	range	kp1	kp1	5	NULL	48	Using index condition; Using where; Rowid-ordered scan
-2	SUBQUERY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t1.c	1	Using index
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	Using where
+1	PRIMARY	t1	ref	kp1	kp1	5	test.t3.a	1	Using where
+1	PRIMARY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t1.c	1	Using index; FirstMatch(t3)
 drop table t1, t3, t4;
 create table t1 (a int) as select * from t0 where a < 5;
 set @save_max_heap_table_size=@@max_heap_table_size;
@@ -1167,9 +1167,8 @@ create table t3 ( a int , filler char(100), key(a));
 insert into t3 select A.a + 10*B.a, 'filler' from t0 A, t0 B;
 explain select * from t3 where a in (select a from t2) and (a > 5 or a < 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	2	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	End temporary
 select * from t3 where a in (select a from t2);
 a	filler
 1	filler
@@ -1215,47 +1214,44 @@ create table t3 (a int, b int, filler char(100), key(a));
 insert into t3 select A.a + 10*B.a, A.a + 10*B.a, 'filler' from t1 A, t1 B, t1 C;
 explain select * from t1, t3 where t3.a in (select a from t2) and (t3.a < 10 or t3.a >30) and t1.a =3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	End temporary
 explain select straight_join * from t1 A, t1 B where A.a in (select a from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
 1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
 explain select * from t2 where a in (select straight_join A.a from t1 A, t1 B);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
-2	SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	
-2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
+2	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using where; Using join buffer (flat, BNL join)
 explain select * from t2 where a in (select straight_join A.a from t1 A, t1 B);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
-2	SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	
-2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
+2	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using where; Using join buffer (flat, BNL join)
 explain select straight_join * from t2 X, t2 Y 
 where X.a in (select straight_join A.a from t1 A, t1 B);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	X	ALL	NULL	NULL	NULL	NULL	10	Using where
 1	PRIMARY	Y	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
-2	SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	
-2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
+2	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using where; Using join buffer (flat, BNL join)
 create table t0 (a int, b int);
 insert into t0 values(1,1);
 explain select * from t0, t3 where t3.a in (select a from t2) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	End temporary
 create table t4 as select a as x, a as y from t1;
 explain select * from t0, t3 where (t3.a, t3.b) in (select x,y from t4) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t4.x	10	Using where
-2	SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t3	ref	a	a	5	test.t4.x	10	Using where; End temporary
 drop table t0,t1,t2,t3,t4;
 create table t0 (a int);
 insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
@@ -1264,14 +1260,12 @@ insert into t1 select A.a, B.a, 'filler' from t0 A, t0 B;
 create table t2 as select * from t1;
 explain select * from t2 where a in (select b from t1 where a=3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	ref	a	a	10	const,test.t2.a	8	Using index
+1	PRIMARY	t1	range	a	a	5	NULL	8	Using where; Using index; LooseScan
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 explain select * from t2 where (b,a) in (select a,b from t1 where a=3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	10	func	1	
-2	SUBQUERY	t1	ref	a	a	10	const,test.t2.a	8	Using index
+1	PRIMARY	t1	range	a	a	5	NULL	8	Using where; Using index; LooseScan
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 drop table t1,t2;
 create table t1 (a int, b int);
 insert into t1 select a,a from t0;
@@ -1280,16 +1274,14 @@ insert into t2 select A.a + 10*B.a, A.a + 10*B.a from t0 A, t0 B;
 set @@optimizer_switch='firstmatch=off';
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	10	func	1	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	100	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Start temporary
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where; End temporary; Using join buffer (flat, BNL join)
 set @save_optimizer_search_depth=@@optimizer_search_depth;
 set @@optimizer_search_depth=63;
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	10	func	1	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	100	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Start temporary
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where; End temporary; Using join buffer (flat, BNL join)
 set @@optimizer_search_depth=@save_optimizer_search_depth;
 set @@optimizer_switch=@save_optimizer_switch;
 drop table t0, t1, t2;
@@ -1299,9 +1291,8 @@ create table t1 as select * from t0;
 insert into t1 select * from t0;
 explain select * from t0 where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	3	func	1	
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	2	Start temporary
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where; End temporary; Using join buffer (flat, BNL join)
 select * from t0 where a in (select a from t1);
 a
 10.24
@@ -1313,9 +1304,8 @@ create table t1 as select * from t0;
 insert into t1 select * from t0;
 explain select * from t0 where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	4	func	1	
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	2	Start temporary
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where; End temporary; Using join buffer (flat, BNL join)
 select * from t0 where a in (select a from t1);
 a
 2008-01-01
@@ -1328,11 +1318,10 @@ create table t2 as select a as a, a as b from t0 where a < 3;
 insert into t2 select * from t2;
 explain select * from t1 where (a,b,c) in (select X.a, Y.a, Z.a from t2 X, t2 Y, t2 Z where X.b=33);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	15	func	1	
-2	SUBQUERY	X	ALL	NULL	NULL	NULL	NULL	6	Using where
-2	SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
-2	SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Start temporary
+1	PRIMARY	X	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	Y	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	Z	ALL	NULL	NULL	NULL	NULL	6	Using where; End temporary; Using join buffer (flat, BNL join)
 drop table t0,t1,t2;
 
 BUG#37842: Assertion in DsMrr_impl::dsmrr_init, at handler.cc:4307
@@ -1402,10 +1391,9 @@ INNER JOIN t2 c ON c.idContact=cona.idContact
 WHERE cona.postalStripped='T2H3B2'
 	);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	2	1.00	
-1	PRIMARY	a	index	PRIMARY	PRIMARY	4	NULL	2	100.00	Using where; Using index; Using join buffer (flat, BNL join)
-2	SUBQUERY	cona	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	SUBQUERY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	
+1	PRIMARY	cona	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Start temporary
+1	PRIMARY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	Using where
+1	PRIMARY	a	eq_ref	PRIMARY	PRIMARY	4	test.c.idObj	1	100.00	Using index; End temporary
 Warnings:
 Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`c`.`idContact` = `test`.`cona`.`idContact`) and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`cona`.`postalStripped` = 'T2H3B2'))
 drop table t1,t2,t3;
diff --git a/mysql-test/r/subselect3_jcl6.result b/mysql-test/r/subselect3_jcl6.result
index b8a30ce1722..c59d11edc5e 100644
--- a/mysql-test/r/subselect3_jcl6.result
+++ b/mysql-test/r/subselect3_jcl6.result
@@ -35,7 +35,7 @@ select a, oref, a in (select max(ie)
 from t1 where oref=t2.oref group by grp) Z from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary
 Warnings:
 Note	1276	Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref`,<expr_cache><`test`.`t2`.`a`,`test`.`t2`.`oref`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select max(`test`.`t1`.`ie`) from `test`.`t1` where (`test`.`t1`.`oref` = `test`.`t2`.`oref`) group by `test`.`t1`.`grp` having trigcond((<cache>(`test`.`t2`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`))))))) AS `Z` from `test`.`t2`
@@ -44,7 +44,7 @@ select a, oref from t2
 where a in (select max(ie) from t1 where oref=t2.oref group by grp);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary
 Warnings:
 Note	1276	Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`,`test`.`t2`.`oref`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select max(`test`.`t1`.`ie`) from `test`.`t1` where (`test`.`t1`.`oref` = `test`.`t2`.`oref`) group by `test`.`t1`.`grp` having (<cache>(`test`.`t2`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`))))))
@@ -76,7 +76,7 @@ set @@optimizer_switch="partial_match_rowid_merge=off,partial_match_table_scan=o
 explain extended select a in (select max(ie) from t1 where oref=4 group by grp) from t3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select <expr_cache><`test`.`t3`.`a`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select max(`test`.`t1`.`ie`) from `test`.`t1` where (`test`.`t1`.`oref` = 4) group by `test`.`t1`.`grp` having trigcond((<cache>(`test`.`t3`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`))))))) AS `a in (select max(ie) from t1 where oref=4 group by grp)` from `test`.`t3`
 set @@optimizer_switch=@save_optimizer_switch;
@@ -128,7 +128,7 @@ Handler_read_key	0
 Handler_read_next	0
 Handler_read_prev	0
 Handler_read_rnd	0
-Handler_read_rnd_next	29
+Handler_read_rnd_next	35
 select 'No key lookups, seq reads: 29= 5 reads from t2 + 4 * 6 reads from t1.' Z;
 Z
 No key lookups, seq reads: 29= 5 reads from t2 + 4 * 6 reads from t1.
@@ -170,7 +170,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref	a	a	5	test.t1.b	1	100.00	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
 Note	1276	Field or reference 'test.t3.oref' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select 1 from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond(((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`)))) having trigcond(<is_not_null_test>(`test`.`t1`.`a`))))) AS `Z` from `test`.`t3`
+Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond(((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`))) and (`test`.`t2`.`a` = `test`.`t1`.`b`)) having trigcond(<is_not_null_test>(`test`.`t1`.`a`))))) AS `Z` from `test`.`t3`
 drop table t1, t2, t3;
 create table t1 (a int NOT NULL, b int NOT NULL, key(a));
 insert into t1 values 
@@ -198,7 +198,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref	a	a	4	test.t1.b	1	100.00	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
 Note	1276	Field or reference 'test.t3.oref' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select 1 from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`)))))) AS `Z` from `test`.`t3`
+Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`)) and (`test`.`t2`.`a` = `test`.`t1`.`b`))))) AS `Z` from `test`.`t3`
 drop table t1,t2,t3;
 create table t1 (oref int, grp int);
 insert into t1 (oref, grp) values
@@ -219,7 +219,7 @@ select a, oref,
 a in (select count(*) from t1 group by grp having grp=t2.oref) Z from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
 Note	1276	Field or reference 't2.oref' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref`,<expr_cache><`test`.`t2`.`a`,`test`.`t2`.`oref`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select count(0) from `test`.`t1` group by `test`.`t1`.`grp` having ((`test`.`t1`.`grp` = `test`.`t2`.`oref`) and trigcond((<cache>(`test`.`t2`.`a`) = <ref_null_helper>(count(0)))))))) AS `Z` from `test`.`t2`
@@ -470,7 +470,7 @@ group by grp having min(ie) > 1) Z
 from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	7	
-2	DEPENDENT SUBQUERY	t1	ref	idx	idx	5	test.t2.oref	2	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ref	idx	idx	5	test.t2.oref	2	Using where; Using temporary
 select oref, a, 
 a in (select min(ie) from t1 where oref=t2.oref 
 group by grp having min(ie) > 1) Z 
@@ -631,7 +631,7 @@ explain
 select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp) Z from t2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	7	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	6	Using where; Using temporary
 select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp) Z from t2;
 oref	a	Z
 ee	NULL	0
@@ -718,7 +718,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	100.00	Using index
 2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t1`.`a`) and (not(<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t1` where ((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`)) having <is_not_null_test>(`test`.`t1`.`a`)))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t1`.`a`) and (not(<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` where trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`))) having trigcond(<is_not_null_test>(`test`.`t1`.`a`))))))))
 SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1));
 a
 SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1 WHERE a > 4));
@@ -739,7 +739,7 @@ WHERE t3.name='xxx' AND t2.id=t3.id);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
 2	DEPENDENT SUBQUERY	t2	eq_ref	PRIMARY	PRIMARY	4	func	1	Using where; Using index; Full scan on NULL key
-2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	func	1	Using index condition(BKA); Using where; Full scan on NULL key; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.id	1	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 SELECT * FROM t1
 WHERE t1.id NOT IN (SELECT t2.id FROM t2,t3 
 WHERE t3.name='xxx' AND t2.id=t3.id);
@@ -848,11 +848,16 @@ x	ROW(11, 12) = (SELECT MAX(x), 22)	ROW(11, 12) IN (SELECT MAX(x), 22)
 1	0	0
 2	0	0
 11	0	0
-# 2nd and 3rd columns should be same for x == 11 only
+# 2nd and 3rd columns should be same
+EXPLAIN SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 12), ROW(11, 12) IN (SELECT MAX(x), 12) FROM t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 12), ROW(11, 12) IN (SELECT MAX(x), 12) FROM t1;
 x	ROW(11, 12) = (SELECT MAX(x), 12)	ROW(11, 12) IN (SELECT MAX(x), 12)
-1	0	1
-2	0	1
+1	0	0
+2	0	0
 11	1	1
 DROP TABLE t1;
 # both columns should be same
@@ -978,7 +983,7 @@ i1	i2
 # Baseline:
 SHOW STATUS LIKE '%Handler_read_rnd_next';
 Variable_name	Value
-Handler_read_rnd_next	18
+Handler_read_rnd_next	17
 
 INSERT INTO t1 VALUES (NULL, NULL);
 FLUSH STATUS;
@@ -995,7 +1000,7 @@ i1	i2
 # (read record from t1, but do not read from t2)
 SHOW STATUS LIKE '%Handler_read_rnd_next';
 Variable_name	Value
-Handler_read_rnd_next	19
+Handler_read_rnd_next	18
 set @@optimizer_switch=@save_optimizer_switch2;
 DROP TABLE t1,t2;
 End of 5.1 tests
@@ -1030,11 +1035,10 @@ update t22 set c = '2005-12-08 15:58:27' where a = 255;
 explain select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	8	Using temporary; Using filesort
-1	PRIMARY	t21	hash_ALL	NULL	#hash#$hj	4	test.t11.a	26	Using where; Using join buffer (flat, BNLH join)
-1	PRIMARY	t22	hash_ALL	NULL	#hash#$hj	4	test.t11.a	26	Using where; Using join buffer (incremental, BNLH join)
-2	SUBQUERY	t11	ALL	NULL	NULL	NULL	NULL	8	Using where
-2	SUBQUERY	t12	hash_ALL	NULL	#hash#$hj	4	test.t11.a	8	Using where; Using join buffer (flat, BNLH join)
+1	PRIMARY	t11	ALL	NULL	NULL	NULL	NULL	8	Using where; Using temporary; Using filesort; Start temporary
+1	PRIMARY	t12	hash_ALL	NULL	#hash#$hj	4	test.t11.a	8	Using where; Using join buffer (flat, BNLH join)
+1	PRIMARY	t22	hash_ALL	NULL	#hash#$hj	4	test.t11.a	26	Using where; End temporary; Using join buffer (incremental, BNLH join)
+1	PRIMARY	t21	hash_ALL	NULL	#hash#$hj	4	test.t11.a	26	Using where; Using join buffer (incremental, BNLH join)
 select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 a	b	c
@@ -1047,9 +1051,8 @@ explain
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	X	ALL	NULL	NULL	NULL	NULL	2	
-2	DEPENDENT SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	subselect3	eq_ref	unique_key	unique_key	5	func	1	
-3	SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	2	
+2	DEPENDENT SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+2	DEPENDENT SUBQUERY	Z	hash_ALL	NULL	#hash#$hj	5	test.Y.a	2	Using where; End temporary; Using join buffer (flat, BNLH join)
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 subq
 NULL
@@ -1119,8 +1122,7 @@ set @@optimizer_switch=@save_optimizer_switch;
 explain select * from (select a from t0) X where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	11	
-1	PRIMARY	subselect3	eq_ref	unique_key	unique_key	5	func	1	
-3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	20	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where; FirstMatch(<derived2>); Using join buffer (flat, BNL join)
 2	DERIVED	t0	ALL	NULL	NULL	NULL	NULL	11	
 drop table t0, t1;
 create table t0 (a int);
@@ -1132,18 +1134,16 @@ create table t3 (a int);
 insert into t3 select A.a + 10*B.a from t0 A, t0 B;
 explain select * from t3 where a in (select kp1 from t1 where kp1<20);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	range	kp1	kp1	5	NULL	48	Using where; Using index
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	Using where
+1	PRIMARY	t1	ref	kp1	kp1	5	test.t3.a	1	Using index; FirstMatch(t3)
 create table t4 (pk int primary key);
 insert into t4 select a from t3;
 explain select * from t3 where a in (select t1.kp1 from t1,t4 where kp1<20
 and t4.pk=t1.c);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	range	kp1	kp1	5	NULL	48	Using index condition; Using where; Rowid-ordered scan
-2	SUBQUERY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t1.c	1	Using index
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	Using where
+1	PRIMARY	t1	ref	kp1	kp1	5	test.t3.a	1	Using where
+1	PRIMARY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t1.c	1	Using index; FirstMatch(t3)
 drop table t1, t3, t4;
 create table t1 (a int) as select * from t0 where a < 5;
 set @save_max_heap_table_size=@@max_heap_table_size;
@@ -1174,9 +1174,8 @@ create table t3 ( a int , filler char(100), key(a));
 insert into t3 select A.a + 10*B.a, 'filler' from t0 A, t0 B;
 explain select * from t3 where a in (select a from t2) and (a > 5 or a < 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	2	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 select * from t3 where a in (select a from t2);
 a	filler
 1	filler
@@ -1222,47 +1221,44 @@ create table t3 (a int, b int, filler char(100), key(a));
 insert into t3 select A.a + 10*B.a, A.a + 10*B.a, 'filler' from t1 A, t1 B, t1 C;
 explain select * from t1, t3 where t3.a in (select a from t2) and (t3.a < 10 or t3.a >30) and t1.a =3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	End temporary; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
 explain select straight_join * from t1 A, t1 B where A.a in (select a from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
 1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
 explain select * from t2 where a in (select straight_join A.a from t1 A, t1 B);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
-2	SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	
-2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
+2	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using where; Using join buffer (flat, BNL join)
 explain select * from t2 where a in (select straight_join A.a from t1 A, t1 B);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
-2	SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	
-2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
+2	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using where; Using join buffer (flat, BNL join)
 explain select straight_join * from t2 X, t2 Y 
 where X.a in (select straight_join A.a from t1 A, t1 B);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	X	ALL	NULL	NULL	NULL	NULL	10	Using where
 1	PRIMARY	Y	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
-2	SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	
-2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
+2	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	Using where; Using join buffer (flat, BNL join)
 create table t0 (a int, b int);
 insert into t0 values(1,1);
 explain select * from t0, t3 where t3.a in (select a from t2) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 create table t4 as select a as x, a as y from t1;
 explain select * from t0, t3 where (t3.a, t3.b) in (select x,y from t4) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t4.x	10	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
-2	SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t3	ref	a	a	5	test.t4.x	10	Using where; End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 drop table t0,t1,t2,t3,t4;
 create table t0 (a int);
 insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
@@ -1271,14 +1267,12 @@ insert into t1 select A.a, B.a, 'filler' from t0 A, t0 B;
 create table t2 as select * from t1;
 explain select * from t2 where a in (select b from t1 where a=3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	ref	a	a	10	const,test.t2.a	8	Using index
+1	PRIMARY	t1	range	a	a	5	NULL	8	Using where; Using index; LooseScan
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 explain select * from t2 where (b,a) in (select a,b from t1 where a=3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	10	func	1	
-2	SUBQUERY	t1	ref	a	a	10	const,test.t2.a	8	Using index
+1	PRIMARY	t1	range	a	a	5	NULL	8	Using where; Using index; LooseScan
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 drop table t1,t2;
 create table t1 (a int, b int);
 insert into t1 select a,a from t0;
@@ -1287,16 +1281,14 @@ insert into t2 select A.a + 10*B.a, A.a + 10*B.a from t0 A, t0 B;
 set @@optimizer_switch='firstmatch=off';
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	10	func	1	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	100	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	10	test.t1.a,test.t1.b	100	Using where; End temporary; Using join buffer (flat, BNLH join)
 set @save_optimizer_search_depth=@@optimizer_search_depth;
 set @@optimizer_search_depth=63;
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	10	func	1	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	100	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	10	test.t1.a,test.t1.b	100	Using where; End temporary; Using join buffer (flat, BNLH join)
 set @@optimizer_search_depth=@save_optimizer_search_depth;
 set @@optimizer_switch=@save_optimizer_switch;
 drop table t0, t1, t2;
@@ -1306,9 +1298,8 @@ create table t1 as select * from t0;
 insert into t1 select * from t0;
 explain select * from t0 where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	3	func	1	
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	t1	hash_ALL	NULL	#hash#$hj	3	test.t0.a	4	Using where; End temporary; Using join buffer (flat, BNLH join)
 select * from t0 where a in (select a from t1);
 a
 10.24
@@ -1320,9 +1311,8 @@ create table t1 as select * from t0;
 insert into t1 select * from t0;
 explain select * from t0 where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	4	func	1	
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	t1	hash_ALL	NULL	#hash#$hj	4	test.t0.a	4	Using where; End temporary; Using join buffer (flat, BNLH join)
 select * from t0 where a in (select a from t1);
 a
 2008-01-01
@@ -1335,11 +1325,10 @@ create table t2 as select a as a, a as b from t0 where a < 3;
 insert into t2 select * from t2;
 explain select * from t1 where (a,b,c) in (select X.a, Y.a, Z.a from t2 X, t2 Y, t2 Z where X.b=33);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	15	func	1	
-2	SUBQUERY	X	ALL	NULL	NULL	NULL	NULL	6	Using where
-2	SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
-2	SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (incremental, BNL join)
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
+1	PRIMARY	X	hash_ALL	NULL	#hash#$hj	5	test.t1.a	6	Using where; Using join buffer (flat, BNLH join)
+1	PRIMARY	Y	hash_ALL	NULL	#hash#$hj	5	test.t1.b	6	Using where; Using join buffer (incremental, BNLH join)
+1	PRIMARY	Z	hash_ALL	NULL	#hash#$hj	5	test.t1.c	6	Using where; End temporary; Using join buffer (incremental, BNLH join)
 drop table t0,t1,t2;
 
 BUG#37842: Assertion in DsMrr_impl::dsmrr_init, at handler.cc:4307
@@ -1409,10 +1398,9 @@ INNER JOIN t2 c ON c.idContact=cona.idContact
 WHERE cona.postalStripped='T2H3B2'
 	);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	2	1.00	
-1	PRIMARY	a	index	PRIMARY	PRIMARY	4	NULL	2	100.00	Using where; Using index; Using join buffer (flat, BNL join)
-2	SUBQUERY	cona	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	SUBQUERY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	cona	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Start temporary
+1	PRIMARY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	a	eq_ref	PRIMARY	PRIMARY	4	test.c.idObj	1	100.00	Using index; End temporary
 Warnings:
 Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`c`.`idContact` = `test`.`cona`.`idContact`) and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`cona`.`postalStripped` = 'T2H3B2'))
 drop table t1,t2,t3;
diff --git a/mysql-test/r/subselect4.result b/mysql-test/r/subselect4.result
index 686840630f1..53fa73aeaee 100644
--- a/mysql-test/r/subselect4.result
+++ b/mysql-test/r/subselect4.result
@@ -15,7 +15,7 @@ ORDER BY count(*);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	index	NULL	a	5	NULL	2	Using where; Using index; Using temporary
 2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
-3	DEPENDENT SUBQUERY	t3	system	NULL	NULL	NULL	NULL	0	const row not found
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 # should not crash the next statement
 SELECT 1 FROM t1
 WHERE NOT EXISTS (SELECT 1 FROM t2 WHERE 1 = (SELECT MIN(t2.b) FROM t3))
@@ -117,14 +117,14 @@ EXPLAIN
 SELECT * FROM t1 WHERE ( a, b ) NOT IN ( SELECT c, d FROM t2 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 x	PRIMARY	x	x	x	x	x	x	x	x
-x	SUBQUERY	x	x	x	x	x	x	x	x
+x	DEPENDENT SUBQUERY	x	x	x	x	x	x	x	x
 SELECT * FROM t1 WHERE ( a, b ) NOT IN ( SELECT c, d FROM t2 );
 a	b
 EXPLAIN
 SELECT * FROM t1 WHERE ( a, b ) NOT IN ( SELECT c, d FROM t2 ) IS NULL;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 SELECT * FROM t1 WHERE ( a, b ) NOT IN ( SELECT c, d FROM t2 ) IS NULL;
 a	b
 1	NULL
@@ -147,28 +147,28 @@ EXPLAIN
 SELECT * FROM t1 WHERE ( a, b ) NOT IN ( SELECT e, f FROM t3 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 x	PRIMARY	x	x	x	x	x	x	x	x
-x	SUBQUERY	x	x	x	x	x	x	x	x
+x	DEPENDENT SUBQUERY	x	x	x	x	x	x	x	x
 SELECT * FROM t1 WHERE ( a, b ) NOT IN ( SELECT e, f FROM t3 );
 a	b
 EXPLAIN
 SELECT * FROM t2 WHERE ( c, d ) NOT IN ( SELECT a, b FROM t1 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 x	PRIMARY	x	x	x	x	x	x	x	x
-x	SUBQUERY	x	x	x	x	x	x	x	x
+x	DEPENDENT SUBQUERY	x	x	x	x	x	x	x	x
 SELECT * FROM t2 WHERE ( c, d ) NOT IN ( SELECT a, b FROM t1 );
 c	d
 EXPLAIN
 SELECT * FROM t3 WHERE ( e, f ) NOT IN ( SELECT c, d FROM t2 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 x	PRIMARY	x	x	x	x	x	x	x	x
-x	SUBQUERY	x	x	x	x	x	x	x	x
+x	DEPENDENT SUBQUERY	x	x	x	x	x	x	x	x
 SELECT * FROM t3 WHERE ( e, f ) NOT IN ( SELECT c, d FROM t2 );
 e	f
 EXPLAIN
 SELECT * FROM t2 WHERE ( c, d ) NOT IN ( SELECT e, f FROM t3 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 x	PRIMARY	x	x	x	x	x	x	x	x
-x	SUBQUERY	x	x	x	x	x	x	x	x
+x	DEPENDENT SUBQUERY	x	x	x	x	x	x	x	x
 SELECT * FROM t2 WHERE ( c, d ) NOT IN ( SELECT e, f FROM t3 );
 c	d
 SELECT * FROM t1 WHERE ( a, b ) NOT IN 
@@ -342,7 +342,7 @@ INSERT INTO t3 VALUES  ('E4','P4',40);
 INSERT INTO t3 VALUES  ('E4','P5',80);
 SET @old_optimizer_switch = @@session.optimizer_switch;
 SET @old_join_cache_level = @@session.join_cache_level;
-SET SESSION optimizer_switch = 'firstmatch=on,loosescan=on,materialization=on,semijoin=on';
+SET SESSION optimizer_switch = 'firstmatch=on,loosescan=on,materialization=on,in_to_exists=off,semijoin=on';
 SET SESSION join_cache_level = 1;
 CREATE UNIQUE INDEX t1_IDX ON t1(EMPNUM);
 EXPLAIN SELECT EMPNAME
@@ -565,7 +565,7 @@ INSERT INTO t3 VALUES  ('E4','P4',40);
 INSERT INTO t3 VALUES  ('E4','P5',80);
 SET @old_optimizer_switch = @@session.optimizer_switch;
 SET @old_join_cache_level = @@session.join_cache_level;
-SET SESSION optimizer_switch = 'firstmatch=on,loosescan=on,materialization=on,semijoin=on';
+SET SESSION optimizer_switch = 'firstmatch=on,loosescan=on,materialization=on,in_to_exists=off,semijoin=on';
 SET SESSION join_cache_level = 1;
 CREATE UNIQUE INDEX t1_IDX ON t1(EMPNUM);
 EXPLAIN SELECT EMPNAME
@@ -726,7 +726,7 @@ INSERT INTO t1 VALUES ('28','6','m'),('29','4','c');
 CREATE TABLE t2 (f11 varchar(1)) ;
 INSERT INTO t2 VALUES ('f'),('d');
 SET @old_optimizer_switch = @@session.optimizer_switch;
-SET SESSION optimizer_switch = 'materialization=on';
+SET SESSION optimizer_switch = 'materialization=on,in_to_exists=off,';
 EXPLAIN
 SELECT * FROM t1
 WHERE f3 = (
@@ -735,7 +735,7 @@ WHERE ( t1.f10 ) IN ( SELECT f11 FROM t2 GROUP BY f11 ));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using temporary; Using filesort
+3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using temporary
 SELECT * FROM t1
 WHERE f3 = (
 SELECT t1.f3 FROM t1
@@ -749,7 +749,7 @@ WHERE ( f10, f10 ) IN ( SELECT f11, f11 FROM t2 GROUP BY f11 ));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using temporary; Using filesort
+3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using temporary
 SELECT * FROM t1
 WHERE f3 = (
 SELECT f3 FROM t1
@@ -763,7 +763,7 @@ drop table t1,t2;
 CREATE TABLE t1 (f1 int, f2 int);
 CREATE TABLE t2 (f3 int, f4 int not null, PRIMARY KEY (f3));
 set @save_optimizer_switch=@@optimizer_switch;
-SET @@optimizer_switch = 'materialization=on,semijoin=off';
+SET @@optimizer_switch = 'materialization=on,in_to_exists=off,semijoin=off';
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -851,10 +851,10 @@ EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2);
 f1	f2
-SET @@optimizer_switch = 'materialization=off,semijoin=off';
+SET @@optimizer_switch = 'materialization=off,in_to_exists=on,semijoin=off';
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -949,25 +949,25 @@ INSERT INTO t1 VALUES (1, 2);
 INSERT INTO t1 VALUES (3, 4);
 INSERT INTO t2 VALUES (5, 6);
 INSERT INTO t2 VALUES (7, 8);
-SET @@optimizer_switch = 'materialization=on,semijoin=off';
+SET @@optimizer_switch = 'materialization=on,in_to_exists=off,semijoin=off';
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2 WHERE f3 > 10);
 f1	f2
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3+f4, min(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3+f4, min(f4) FROM t2 WHERE f3 > 10);
 f1	f2
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4)+max(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4)+max(f4) FROM t2 WHERE f3 > 10);
 f1	f2
@@ -982,14 +982,14 @@ NULL
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, count(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, count(f4) FROM t2 WHERE f3 > 10);
 f1	f2
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, f3 + count(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, f3 + count(f4) FROM t2 WHERE f3 > 10);
 f1	f2
@@ -1036,29 +1036,29 @@ NULL
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2 WHERE f3 > 10);
 f1	f2
-SET @@optimizer_switch = 'materialization=off,semijoin=off';
+SET @@optimizer_switch = 'materialization=off,in_to_exists=on,semijoin=off';
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	DEPENDENT SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2 WHERE f3 > 10);
 f1	f2
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3+f4, min(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	DEPENDENT SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3+f4, min(f4) FROM t2 WHERE f3 > 10);
 f1	f2
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4)+max(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	DEPENDENT SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4)+max(f4) FROM t2 WHERE f3 > 10);
 f1	f2
@@ -1073,14 +1073,14 @@ NULL
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, count(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	DEPENDENT SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, count(f4) FROM t2 WHERE f3 > 10);
 f1	f2
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, f3 + count(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	DEPENDENT SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	1	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, f3 + count(f4) FROM t2 WHERE f3 > 10);
 f1	f2
@@ -1127,7 +1127,7 @@ NULL
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2 WHERE f3 > 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2 WHERE f3 > 10);
 f1	f2
@@ -1154,20 +1154,21 @@ PRIMARY KEY (pk),
 KEY f2 (f2));
 INSERT INTO t2 VALUES (1,7,'p');
 set @save_optimizer_switch=@@optimizer_switch;
-set @@optimizer_switch='materialization=off,semijoin=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
 EXPLAIN
 SELECT t1.f3, MAX(t1.f2)
 FROM t1, t2
 WHERE (t2.pk = t1.pk) AND t2.pk IN (SELECT f2 FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	t2	system	PRIMARY	NULL	NULL	NULL	1	
+1	PRIMARY	t1	const	PRIMARY	PRIMARY	4	const	1	
 2	DEPENDENT SUBQUERY	t1	index_subquery	f2	f2	4	func	2	Using index
 SELECT t1.f3, MAX(t1.f2)
 FROM t1, t2
 WHERE (t2.pk = t1.pk) AND t2.pk IN (SELECT f2 FROM t1);
 f3	MAX(t1.f2)
 NULL	NULL
-set @@optimizer_switch='materialization=on,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 EXPLAIN
 SELECT t1.f3, MAX(t1.f2)
 FROM t1, t2
@@ -1185,3 +1186,517 @@ TODO: add a test case for semijoin when the wrong result is fixed
 set @@optimizer_switch='materialization=off,semijoin=on';
 set @@optimizer_switch=@save_optimizer_switch;
 drop table t1, t2;
+#
+# LP BUG#641203 Query returns rows where no result is expected (impossible WHERE)
+#
+CREATE TABLE t1 (c1 varchar(1) DEFAULT NULL);
+CREATE TABLE t2 (c1 varchar(1) DEFAULT NULL);
+INSERT INTO t2 VALUES ('k'), ('d');
+CREATE TABLE t3 (c1 varchar(1) DEFAULT NULL);
+INSERT INTO t3 VALUES ('a'), ('b'), ('c');
+CREATE TABLE t4 (c1 varchar(1) primary key);
+INSERT INTO t4 VALUES ('k'), ('d');
+EXPLAIN
+SELECT * FROM t1 RIGHT JOIN t2 ON t1.c1 WHERE 's' IN (SELECT c1 FROM t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+SELECT * FROM t1 RIGHT JOIN t2 ON t1.c1 WHERE 's' IN (SELECT c1 FROM t2);
+c1	c1
+EXPLAIN
+SELECT * FROM t2 LEFT JOIN t1 ON t1.c1 WHERE 's' IN (SELECT c1 FROM t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+SELECT * FROM t2 LEFT JOIN t1 ON t1.c1 WHERE 's' IN (SELECT c1 FROM t2);
+c1	c1
+EXPLAIN
+SELECT * FROM (t2 LEFT JOIN t1 ON t1.c1) LEFT JOIN t3 on t3.c1 WHERE 's' IN (SELECT c1 FROM t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+SELECT * FROM (t2 LEFT JOIN t1 ON t1.c1) LEFT JOIN t3 on t3.c1 WHERE 's' IN (SELECT c1 FROM t2);
+c1	c1	c1
+EXPLAIN
+SELECT * FROM t4 LEFT JOIN t2 ON t4.c1 WHERE 's' IN (SELECT c1 FROM t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t4	index	NULL	PRIMARY	3	NULL	2	Using index
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+SELECT * FROM t4 LEFT JOIN t2 ON t4.c1 WHERE 's' IN (SELECT c1 FROM t2);
+c1	c1
+drop table t1, t2, t3, t4;
+#
+# LP BUG#675981 Assertion `cache != __null' failed in sub_select_cache()
+#               on EXPLAIN
+#
+CREATE TABLE t1 (f1 int,f2 int) ;
+INSERT IGNORE INTO t1 VALUES ('2','5'),('2',NULL);
+CREATE TABLE t2 (f1 int, f5 int) ;
+INSERT IGNORE INTO t2 VALUES (1,0);
+CREATE TABLE t3 (f4 int) ;
+INSERT IGNORE INTO t3 VALUES (0),(0);
+set @@optimizer_switch='in_to_exists=on,materialization=off,semijoin=off';
+EXPLAIN
+SELECT * FROM t2
+WHERE f1 IN (SELECT t1.f2 FROM t1 JOIN t3 ON t3.f4);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
+drop table t1, t2, t3;
+#
+# LP BUG#680005 Second assertion `cache != __null' failed in
+#                sub_select_cache() on EXPLAIN
+#
+CREATE TABLE t1 (f1 int,f2 int,f4 int,f6 int,KEY (f4)) ;
+INSERT IGNORE INTO t1 VALUES
+('1','5','1','0'),('2','1','1','0'),('2','2','2','0'),('0',NULL,'0','0'),
+('2','1','2','0'),('2','0','0','0'),('2','2','2','0'),('2','8','2','0'),
+('2','7','2','0'),('2','5','2','0'),('2',NULL,'1','0');
+CREATE TABLE t2 (f3 int) ;
+INSERT IGNORE INTO t2 VALUES ('7');
+CREATE TABLE t3 (f3 int) ;
+INSERT IGNORE INTO t3 VALUES ('2');
+EXPLAIN
+SELECT t1.f4
+FROM t2 JOIN t1 ON t1.f6
+WHERE
+( t1.f2 ) IN (SELECT SUBQUERY2_t1.f3
+FROM t3 AS SUBQUERY2_t1
+JOIN
+(t1 AS SUBQUERY2_t2
+JOIN
+t1 AS SUBQUERY2_t3 ON SUBQUERY2_t3.f1)
+ON SUBQUERY2_t3.f2)
+GROUP BY t1.f4 ORDER BY t1.f1 LIMIT 10;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	Using temporary; Using filesort
+1	PRIMARY	t1	index	NULL	f4	5	NULL	11	Using where
+2	DEPENDENT SUBQUERY	SUBQUERY2_t1	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	SUBQUERY2_t2	index	NULL	f4	5	NULL	11	Using index
+2	DEPENDENT SUBQUERY	SUBQUERY2_t3	ALL	NULL	NULL	NULL	NULL	11	Using where; Using join buffer (flat, BNL join)
+drop table t1, t2, t3;
+#
+# LP BUG#680038 bool close_thread_table(THD*, TABLE**):
+#               Assertion `table->key_read == 0' failed in EXPLAIN
+#
+CREATE TABLE t1 (f1 int,f3 int,f4 int) ;
+INSERT IGNORE INTO t1 VALUES (NULL,1,0);
+CREATE TABLE t2 (f2 int,f4 int,f5 int) ;
+INSERT IGNORE INTO t2 VALUES (8,0,0),(5,0,0);
+CREATE TABLE t3 (f4 int,KEY (f4)) ;
+INSERT IGNORE INTO t3 VALUES (0),(0);
+set @@optimizer_switch='semijoin=off';
+EXPLAIN
+SELECT * FROM t1 WHERE
+(SELECT f2 FROM t2
+WHERE f4 <= ALL
+(SELECT SQ1_t1.f4
+FROM t3 AS SQ1_t1 JOIN t3 AS SQ1_t3 ON SQ1_t3.f4
+GROUP BY SQ1_t1.f4));
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+3	SUBQUERY	SQ1_t1	index	NULL	f4	5	NULL	2	Using index; Using temporary
+3	SUBQUERY	SQ1_t3	index	NULL	f4	5	NULL	2	Using where; Using index; Using join buffer (flat, BNL join)
+drop table t1, t2, t3;
+#
+# BUG#52317: Assertion failing in Field_varstring::store() 
+# 	    at field.cc:6833
+#
+CREATE TABLE t1 (i INTEGER);
+INSERT INTO t1 VALUES (1);
+CREATE TABLE t2 (i INTEGER, KEY k(i));
+INSERT INTO t2 VALUES (1), (2);
+EXPLAIN  
+SELECT i FROM t1 WHERE (1) NOT IN (SELECT i FROM t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	t2	ref_or_null	k	k	5	const	2	Using where; Using index
+DROP TABLE t2;
+DROP TABLE t1;
+#
+# LP BUG#680846: Crash in clear_tables() with subqueries
+#
+CREATE TABLE t1 (f3 int) ;
+INSERT IGNORE INTO t1 VALUES (0),(0);
+CREATE TABLE t2 (f1 int,f3 int,f4 varchar(32)) ;
+INSERT IGNORE INTO t2 VALUES (1,0,'f');
+EXPLAIN
+SELECT COUNT(t2.f3),
+(SELECT COUNT(f3) FROM t1 WHERE t2.f1) AS f9
+FROM t2 JOIN t1 ON t1.f3
+WHERE ('v') IN (SELECT f4 FROM t2)
+GROUP BY f9;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT COUNT(t2.f3),
+(SELECT COUNT(f3) FROM t1 WHERE t2.f1) AS f9
+FROM t2 JOIN t1 ON t1.f3
+WHERE ('v') IN (SELECT f4 FROM t2)
+GROUP BY f9;
+COUNT(t2.f3)	f9
+EXPLAIN
+SELECT COUNT(t2.f3),
+(SELECT COUNT(f3) FROM t1 WHERE t2.f1) AS f9
+FROM t2 JOIN t1 ON t1.f3
+WHERE ('v') IN (SELECT f4 FROM t2)
+ORDER BY f9;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT COUNT(t2.f3),
+(SELECT COUNT(f3) FROM t1 WHERE t2.f1) AS f9
+FROM t2 JOIN t1 ON t1.f3
+WHERE ('v') IN (SELECT f4 FROM t2)
+ORDER BY f9;
+COUNT(t2.f3)	f9
+0	2
+EXPLAIN
+SELECT COUNT(t2.f3),
+(SELECT t2.f1 FROM t1 limit 1) AS f9
+FROM t2 JOIN t1
+WHERE ('v') IN (SELECT f4 FROM t2)
+GROUP BY f9;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT COUNT(t2.f3),
+(SELECT t2.f1 FROM t1 limit 1) AS f9
+FROM t2 JOIN t1
+WHERE ('v') IN (SELECT f4 FROM t2)
+GROUP BY f9;
+COUNT(t2.f3)	f9
+EXPLAIN
+SELECT COUNT(t2.f3),
+(SELECT t2.f1 FROM t1 limit 1) AS f9
+FROM t2 JOIN t1
+WHERE ('v') IN (SELECT f4 FROM t2)
+ORDER BY f9;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT COUNT(t2.f3),
+(SELECT t2.f1 FROM t1 limit 1) AS f9
+FROM t2 JOIN t1
+WHERE ('v') IN (SELECT f4 FROM t2)
+ORDER BY f9;
+COUNT(t2.f3)	f9
+0	NULL
+drop table t1,t2;
+#
+# LP BUG#682683 Crash in create_tmp_table called from
+#               JOIN::init_execution
+#
+CREATE TABLE t2 (f1 int) ;
+INSERT INTO t2 VALUES (1),(2);
+CREATE TABLE t1 (f1 int) ;
+EXPLAIN
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 GROUP BY field1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	SUBQUERY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 GROUP BY field1;
+field1
+NULL
+EXPLAIN
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 ORDER BY field1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	SUBQUERY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 ORDER BY field1;
+field1
+NULL
+NULL
+INSERT INTO t1 VALUES (1),(2);
+EXPLAIN
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 GROUP BY field1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 GROUP BY field1;
+ERROR 21000: Subquery returns more than 1 row
+EXPLAIN
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 ORDER BY field1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 ORDER BY field1;
+ERROR 21000: Subquery returns more than 1 row
+drop table t1,t2;
+#
+# LP BUG#680943 Assertion `!table || (!table->read_set ||
+# bitmap_is_set(table->read_set, field_index))' failed with subquery
+#
+CREATE TABLE t1 (f1 int,f3 int) ;
+INSERT IGNORE INTO t1 VALUES ('6','0'),('4','0');
+CREATE TABLE t2 (f1 int,f2 int,f3 int) ;
+INSERT IGNORE INTO t2 VALUES ('6','0','0'),('2','0','0');
+SELECT f2
+FROM (SELECT * FROM t2) AS alias1
+WHERE (SELECT SQ2_t2.f1
+FROM t1 JOIN t1 AS SQ2_t2 ON SQ2_t2.f3
+WHERE SQ2_t2.f3 AND alias1.f1)
+ORDER BY f3 ;
+f2
+drop table t1,t2;
+#
+# LP BUG#715062: Wrong result with VIEW + UNION + subquery in maria-5.3-mwl89
+#
+create table t1 (f1 int);
+create table t2 (f2 int);
+create table t3 (f3 int);
+insert into t1 values (2);
+insert into t2 values (2);
+insert into t3 values (7);
+CREATE VIEW v1 AS SELECT 2 UNION SELECT 2 ;
+CREATE VIEW v2 AS SELECT * from t1 UNION SELECT * from t2 ;
+set @save_optimizer_switch=@@optimizer_switch;
+SET @@optimizer_switch = 'in_to_exists=off,semijoin=off,materialization=on';
+EXPLAIN
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN ( SELECT * FROM v1 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+4	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN ( SELECT * FROM v1 );
+bug
+EXPLAIN
+SELECT ( 5 ) IN ( SELECT * FROM v1 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+4	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT ( 5 ) IN ( SELECT * FROM v1 );
+( 5 ) IN ( SELECT * FROM v1 )
+0
+EXPLAIN
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN (SELECT * FROM v2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	t1	system	NULL	NULL	NULL	NULL	1	
+4	UNION	t2	system	NULL	NULL	NULL	NULL	1	
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN (SELECT * FROM v2);
+bug
+EXPLAIN
+SELECT 'bug' FROM t3 WHERE ( 5 ) IN (SELECT * FROM v2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t3	system	NULL	NULL	NULL	NULL	1	
+2	SUBQUERY	<derived3>	system	NULL	NULL	NULL	NULL	1	
+3	DERIVED	t1	system	NULL	NULL	NULL	NULL	1	
+4	UNION	t2	system	NULL	NULL	NULL	NULL	1	
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT 'bug' FROM t3 WHERE ( 5 ) IN (SELECT * FROM v2);
+bug
+EXPLAIN
+SELECT ( 5 ) IN ( SELECT * FROM v2 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	t1	system	NULL	NULL	NULL	NULL	1	
+4	UNION	t2	system	NULL	NULL	NULL	NULL	1	
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT ( 5 ) IN ( SELECT * FROM v2 );
+( 5 ) IN ( SELECT * FROM v2 )
+0
+SET @@optimizer_switch = 'in_to_exists=on,semijoin=off,materialization=off';
+EXPLAIN
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN ( SELECT * FROM v1 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+4	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN ( SELECT * FROM v1 );
+bug
+EXPLAIN
+SELECT ( 5 ) IN ( SELECT * FROM v1 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+4	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT ( 5 ) IN ( SELECT * FROM v1 );
+( 5 ) IN ( SELECT * FROM v1 )
+0
+EXPLAIN
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN (SELECT * FROM v2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	t1	system	NULL	NULL	NULL	NULL	1	
+4	UNION	t2	system	NULL	NULL	NULL	NULL	1	
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN (SELECT * FROM v2);
+bug
+EXPLAIN
+SELECT 'bug' FROM t3 WHERE ( 5 ) IN (SELECT * FROM v2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t3	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	t1	system	NULL	NULL	NULL	NULL	1	
+4	UNION	t2	system	NULL	NULL	NULL	NULL	1	
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT 'bug' FROM t3 WHERE ( 5 ) IN (SELECT * FROM v2);
+bug
+EXPLAIN
+SELECT ( 5 ) IN ( SELECT * FROM v2 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DERIVED	t1	system	NULL	NULL	NULL	NULL	1	
+4	UNION	t2	system	NULL	NULL	NULL	NULL	1	
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+SELECT ( 5 ) IN ( SELECT * FROM v2 );
+( 5 ) IN ( SELECT * FROM v2 )
+0
+set @@optimizer_switch=@save_optimizer_switch;
+drop table t1,t2,t3;
+drop view v1,v2;
+#
+# LP BUG#715069 Wrong result with GROUP BY inside subquery and materialization=off
+#
+CREATE TABLE t0 ( f1 int(11), f2 int(11), f10 varchar(1), PRIMARY KEY (f1)) ;
+INSERT INTO t0 VALUES (8,8,'u'),(10,5,'o');
+CREATE TABLE t1 (f1a int, f2a int not null, f3a varchar(3) not null, PRIMARY KEY (f1a)) ;
+INSERT INTO t1 VALUES
+(8,8,'a1a'),
+(10,5,'b1b');
+CREATE TABLE t2 (f1b int, f2b int not null, f3b varchar(3) not null, PRIMARY KEY (f1b)) ;
+INSERT INTO t2 VALUES
+(10,5,'d1d');
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off';
+EXPLAIN
+SELECT alias2.f1 , alias2.f2
+FROM t0 AS alias1
+RIGHT JOIN t0 AS alias2 ON alias2.f10
+WHERE ( alias2.f1 , alias2.f2 ) IN ( SELECT f2 , f1 FROM t0 GROUP BY f2 , f1 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	alias2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	alias1	index	NULL	PRIMARY	4	NULL	2	Using where; Using index
+2	DEPENDENT SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	2	
+SELECT alias2.f1 , alias2.f2
+FROM t0 AS alias1
+RIGHT JOIN t0 AS alias2 ON alias2.f10
+WHERE ( alias2.f1 , alias2.f2 ) IN ( SELECT f2 , f1 FROM t0 GROUP BY f2 , f1 );
+f1	f2
+8	8
+EXPLAIN
+SELECT * FROM t2 WHERE (f1b, f2b) IN (SELECT f1a, f2a FROM t1 GROUP BY f1a, f2a);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT * FROM t2 WHERE (f1b, f2b) IN (SELECT f1a, f2a FROM t1 GROUP BY f1a, f2a);
+f1b	f2b	f3b
+10	5	d1d
+EXPLAIN
+SELECT * FROM t2 WHERE (f1b) IN (SELECT f1a FROM t1 GROUP BY f1a, f2a);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT * FROM t2 WHERE (f1b) IN (SELECT f1a FROM t1 GROUP BY f1a, f2a);
+f1b	f2b	f3b
+10	5	d1d
+SET @@optimizer_switch = 'materialization=on';
+EXPLAIN
+SELECT alias2.f1 , alias2.f2
+FROM t0 AS alias1
+RIGHT JOIN t0 AS alias2 ON alias2.f10
+WHERE ( alias2.f1 , alias2.f2 ) IN ( SELECT f2 , f1 FROM t0 GROUP BY f2 , f1 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	alias2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	alias1	index	NULL	PRIMARY	4	NULL	2	Using where; Using index
+2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	2	
+SELECT alias2.f1 , alias2.f2
+FROM t0 AS alias1
+RIGHT JOIN t0 AS alias2 ON alias2.f10
+WHERE ( alias2.f1 , alias2.f2 ) IN ( SELECT f2 , f1 FROM t0 GROUP BY f2 , f1 );
+f1	f2
+8	8
+EXPLAIN
+SELECT * FROM t2 WHERE (f1b, f2b) IN (SELECT f1a, f2a FROM t1 GROUP BY f1a, f2a);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT * FROM t2 WHERE (f1b, f2b) IN (SELECT f1a, f2a FROM t1 GROUP BY f1a, f2a);
+f1b	f2b	f3b
+10	5	d1d
+EXPLAIN
+SELECT * FROM t2 WHERE (f1b) IN (SELECT f1a FROM t1 GROUP BY f1a, f2a);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT * FROM t2 WHERE (f1b) IN (SELECT f1a FROM t1 GROUP BY f1a, f2a);
+f1b	f2b	f3b
+10	5	d1d
+set @@optimizer_switch=@save_optimizer_switch;
+drop table t0,t1,t2;
+#                                                                                                                                                     
+# LP BUG#718593 Crash in substitute_for_best_equal_field -> eliminate_item_equal -> 
+# Item_field::find_item_equal -> Item_equal::contains
+#                                                                                                                                                     
+set @save_optimizer_switch=@@optimizer_switch;
+SET @@optimizer_switch = 'semijoin=off';
+CREATE TABLE t1 ( f3 int(11), f10 varchar(1), f11 varchar(1)) ;
+INSERT IGNORE INTO t1 VALUES (6,'f','f'),(2,'d','d');
+CREATE TABLE t2 ( f12 int(11), f13 int(11)) ;
+insert into t2 values (1,2), (3,4);
+EXPLAIN
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+SELECT alias2.f3
+FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
+WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
+);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	alias1	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	alias2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+SELECT alias2.f3
+FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
+WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
+);
+f12	f13
+EXPLAIN
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+SELECT alias2.f3
+FROM t1 AS alias1, t1 AS alias2
+WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	alias1	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	alias2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+SELECT alias2.f3
+FROM t1 AS alias1, t1 AS alias2
+WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+f12	f13
+set @@optimizer_switch=@save_optimizer_switch;
+drop table t1, t2;
diff --git a/mysql-test/r/subselect_cache.result b/mysql-test/r/subselect_cache.result
index 7b9dc3c943f..f80b9882c60 100644
--- a/mysql-test/r/subselect_cache.result
+++ b/mysql-test/r/subselect_cache.result
@@ -456,8 +456,8 @@ Handler_read_first	0
 Handler_read_key	7
 Handler_read_next	0
 Handler_read_prev	0
-Handler_read_rnd	0
-Handler_read_rnd_next	31
+Handler_read_rnd	10
+Handler_read_rnd_next	42
 set optimizer_switch='subquery_cache=off';
 flush status;
 select a from t1 ORDER BY (select d from t2 where b=c);
@@ -482,8 +482,8 @@ Handler_read_first	0
 Handler_read_key	0
 Handler_read_next	0
 Handler_read_prev	0
-Handler_read_rnd	0
-Handler_read_rnd_next	61
+Handler_read_rnd	10
+Handler_read_rnd_next	72
 set optimizer_switch='subquery_cache=on';
 #single value subquery test (distinct ORDER BY)
 flush status;
@@ -1336,11 +1336,11 @@ Subquery_cache_miss	0
 show status like '%Handler_read%';
 Variable_name	Value
 Handler_read_first	0
-Handler_read_key	11
+Handler_read_key	0
 Handler_read_next	0
 Handler_read_prev	0
 Handler_read_rnd	0
-Handler_read_rnd_next	145
+Handler_read_rnd_next	188
 set optimizer_switch='subquery_cache=on';
 flush status;
 select a, b , exists (select * from t2 where b=d) as SUBSE, b in (select d from t2) as SUBSI, (select d from t2 where b=c) SUBSR from t1;
@@ -1364,11 +1364,11 @@ Subquery_cache_miss	18
 show status like '%Handler_read%';
 Variable_name	Value
 Handler_read_first	0
-Handler_read_key	32
+Handler_read_key	27
 Handler_read_next	0
 Handler_read_prev	0
 Handler_read_rnd	0
-Handler_read_rnd_next	84
+Handler_read_rnd_next	102
 #several subqueries (several levels)
 set optimizer_switch='subquery_cache=off';
 flush status;
@@ -3195,7 +3195,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where <expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t2` where (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`b`))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where <expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`b` from `test`.`t2` where (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`b`))))
 drop table t1,t2;
 set @@optimizer_switch= default;
 # LP BUG#615760 (part 2: incorrect heap table index flags)
diff --git a/mysql-test/r/subselect_mat.result b/mysql-test/r/subselect_mat.result
index 7b7c2fe3a59..f475b251235 100644
--- a/mysql-test/r/subselect_mat.result
+++ b/mysql-test/r/subselect_mat.result
@@ -30,7 +30,7 @@ create index it3i3 on t3i (c1, c2);
 insert into t1i select * from t1;
 insert into t2i select * from t2;
 insert into t3i select * from t3;
-set @@optimizer_switch='semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 /******************************************************************************
 * Simple tests.
 ******************************************************************************/
@@ -50,7 +50,7 @@ explain extended
 select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t1`.`a1`,`test`.`t1`.`a1` in ( <materialize> (select `test`.`t2`.`b1` from `test`.`t2` where (`test`.`t2`.`b1` > '0') group by `test`.`t2`.`b1` ), <primary_index_lookup>(`test`.`t1`.`a1` in <temporary table> on distinct_key where ((`test`.`t1`.`a1` = `materialized subselect`.`b1`))))))
 select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
@@ -61,7 +61,7 @@ explain extended
 select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),(`test`.`t1`.`a1`,`test`.`t1`.`a2`) in ( <materialize> (select `test`.`t2`.`b1`,`test`.`t2`.`b2` from `test`.`t2` where (`test`.`t2`.`b1` > '0') group by `test`.`t2`.`b1`,`test`.`t2`.`b2` ), <primary_index_lookup>(`test`.`t1`.`a1` in <temporary table> on distinct_key where ((`test`.`t1`.`a1` = `materialized subselect`.`b1`) and (`test`.`t1`.`a2` = `materialized subselect`.`b2`))))))
 select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
@@ -72,7 +72,7 @@ explain extended
 select * from t1 where (a1, a2) in (select b1, min(b2) from t2 where b1 > '0' group by b1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),(`test`.`t1`.`a1`,`test`.`t1`.`a2`) in ( <materialize> (select `test`.`t2`.`b1`,min(`test`.`t2`.`b2`) from `test`.`t2` where (`test`.`t2`.`b1` > '0') group by `test`.`t2`.`b1` ), <primary_index_lookup>(`test`.`t1`.`a1` in <temporary table> on distinct_key where ((`test`.`t1`.`a1` = `materialized subselect`.`b1`) and (`test`.`t1`.`a2` = `materialized subselect`.`min(b2)`))))))
 select * from t1 where (a1, a2) in (select b1, min(b2) from t2 where b1 > '0' group by b1);
@@ -176,33 +176,33 @@ a1	a2
 1 - 02	2 - 02
 select * from t1 where (a1, a2) in (select b1, min(b2) from t2i limit 1,1);
 ERROR 42000: This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=on';
 prepare st1 from
 "select * from t1 where (a1, a2) in (select b1, min(b2) from t2 where b1 > '0' group by b1)";
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=on';
 execute st1;
 a1	a2
 1 - 01	2 - 01
 1 - 02	2 - 02
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=on';
 execute st1;
 a1	a2
 1 - 01	2 - 01
 1 - 02	2 - 02
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=on';
 prepare st1 from
 "select * from t1 where (a1, a2) in (select b1, min(b2) from t2 where b1 > '0' group by b1)";
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 execute st1;
 a1	a2
 1 - 01	2 - 01
 1 - 02	2 - 02
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=on';
 execute st1;
 a1	a2
 1 - 01	2 - 01
 1 - 02	2 - 02
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 explain extended
 select * from t1 where (a1, a2) in (select b1, b2 from t2 order by b1, b2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
@@ -342,7 +342,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3a	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.a1' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where (<expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select `test`.`t2`.`b1`,`test`.`t2`.`b2` from `test`.`t2` where ((<expr_cache><`test`.`t2`.`b2`,`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t2`.`b2`,<exists>(select 1 from `test`.`t3` `t3a` where ((`test`.`t3a`.`c1` = `test`.`t1`.`a1`) and (<cache>(`test`.`t2`.`b2`) = `test`.`t3a`.`c2`))))) or <expr_cache><`test`.`t2`.`b2`>(<in_optimizer>(`test`.`t2`.`b2`,`test`.`t2`.`b2` in ( <materialize> (select `test`.`t3b`.`c2` from `test`.`t3` `t3b` where (`test`.`t3b`.`c2` like '%03') ), <primary_index_lookup>(`test`.`t2`.`b2` in <temporary table> on distinct_key where ((`test`.`t2`.`b2` = `materialized subselect`.`c2`))))))) and (<cache>(`test`.`t1`.`a1`) = `test`.`t2`.`b1`) and (<cache>(`test`.`t1`.`a2`) = `test`.`t2`.`b2`))))) and <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),(`test`.`t1`.`a1`,`test`.`t1`.`a2`) in ( <materialize> (select `test`.`t3c`.`c1`,`test`.`t3c`.`c2` from `test`.`t3` `t3c` where <expr_cache><`test`.`t3c`.`c2`,`test`.`t3c`.`c1`>(<in_optimizer>((`test`.`t3c`.`c1`,`test`.`t3c`.`c2`),(`test`.`t3c`.`c1`,`test`.`t3c`.`c2`) in ( <materialize> (select `test`.`t2i`.`b1`,`test`.`t2i`.`b2` from `test`.`t2i` where (`test`.`t2i`.`b2` > '0') ), <primary_index_lookup>(`test`.`t3c`.`c1` in <temporary table> on distinct_key where ((`test`.`t3c`.`c1` = `materialized subselect`.`b1`) and (`test`.`t3c`.`c2` = `materialized subselect`.`b2`)))))) ), <primary_index_lookup>(`test`.`t1`.`a1` in <temporary table> on distinct_key where ((`test`.`t1`.`a1` = `materialized subselect`.`c1`) and (`test`.`t1`.`a2` = `materialized subselect`.`c2`)))))))
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where (<expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select `test`.`t2`.`b1`,`test`.`t2`.`b2` from `test`.`t2` where ((<expr_cache><`test`.`t2`.`b2`,`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t2`.`b2`,<exists>(select `test`.`t3a`.`c2` from `test`.`t3` `t3a` where ((`test`.`t3a`.`c1` = `test`.`t1`.`a1`) and (<cache>(`test`.`t2`.`b2`) = `test`.`t3a`.`c2`))))) or <expr_cache><`test`.`t2`.`b2`>(<in_optimizer>(`test`.`t2`.`b2`,`test`.`t2`.`b2` in ( <materialize> (select `test`.`t3b`.`c2` from `test`.`t3` `t3b` where (`test`.`t3b`.`c2` like '%03') ), <primary_index_lookup>(`test`.`t2`.`b2` in <temporary table> on distinct_key where ((`test`.`t2`.`b2` = `materialized subselect`.`c2`))))))) and (<cache>(`test`.`t1`.`a1`) = `test`.`t2`.`b1`) and (<cache>(`test`.`t1`.`a2`) = `test`.`t2`.`b2`))))) and <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),(`test`.`t1`.`a1`,`test`.`t1`.`a2`) in ( <materialize> (select `test`.`t3c`.`c1`,`test`.`t3c`.`c2` from `test`.`t3` `t3c` where <expr_cache><`test`.`t3c`.`c2`,`test`.`t3c`.`c1`>(<in_optimizer>((`test`.`t3c`.`c1`,`test`.`t3c`.`c2`),(`test`.`t3c`.`c1`,`test`.`t3c`.`c2`) in ( <materialize> (select `test`.`t2i`.`b1`,`test`.`t2i`.`b2` from `test`.`t2i` where (`test`.`t2i`.`b2` > '0') ), <primary_index_lookup>(`test`.`t3c`.`c1` in <temporary table> on distinct_key where ((`test`.`t3c`.`c1` = `materialized subselect`.`b1`) and (`test`.`t3c`.`c2` = `materialized subselect`.`b2`)))))) ), <primary_index_lookup>(`test`.`t1`.`a1` in <temporary table> on distinct_key where ((`test`.`t1`.`a1` = `materialized subselect`.`c1`) and (`test`.`t1`.`a2` = `materialized subselect`.`c2`)))))))
 select * from t1
 where (a1, a2) in (select b1, b2 from t2
 where b2 in (select c2 from t3 t3a where c1 = a1) or
@@ -369,7 +369,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 5	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 6	SUBQUERY	t2i	index	it2i2	it2i3	18	NULL	5	100.00	Using where; Using index
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using temporary
 4	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 3	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 7	UNION	t1i	index	NULL	it1i3	18	NULL	3	100.00	Using where; Using index
@@ -452,7 +452,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT UNION	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select `test`.`t3`.`c1` AS `c1`,`test`.`t3`.`c2` AS `c2` from `test`.`t3` where <expr_cache><`test`.`t3`.`c1`>(<in_optimizer>(`test`.`t3`.`c1`,<exists>(select 1 from `test`.`t1` where ((`test`.`t1`.`a1` > '0') and (<cache>(`test`.`t3`.`c1`) = `test`.`t1`.`a1`)) union select 1 from `test`.`t2` where ((`test`.`t2`.`b1` < '9') and (<cache>(`test`.`t3`.`c1`) = `test`.`t2`.`b1`)))))
+Note	1003	select `test`.`t3`.`c1` AS `c1`,`test`.`t3`.`c2` AS `c2` from `test`.`t3` where <expr_cache><`test`.`t3`.`c1`>(<in_optimizer>(`test`.`t3`.`c1`,<exists>(select `test`.`t1`.`a1` from `test`.`t1` where ((`test`.`t1`.`a1` > '0') and (<cache>(`test`.`t3`.`c1`) = `test`.`t1`.`a1`)) union select `test`.`t2`.`b1` from `test`.`t2` where ((`test`.`t2`.`b1` < '9') and (<cache>(`test`.`t3`.`c1`) = `test`.`t2`.`b1`)))))
 select * from t3
 where c1 in (select a1 from t1 where a1 > '0' UNION select b1 from t2 where b1 < '9');
 c1	c2
@@ -476,14 +476,14 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 Warnings:
 Note	1276	Field or reference 'test.t1.a1' of SELECT #3 was resolved in SELECT #1
 Note	1276	Field or reference 'test.t1.a2' of SELECT #6 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where (<expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select `test`.`t2`.`b1`,`test`.`t2`.`b2` from `test`.`t2` where ((<expr_cache><`test`.`t2`.`b2`,`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t2`.`b2`,<exists>(select 1 from `test`.`t3` `t3a` where ((`test`.`t3a`.`c1` = `test`.`t1`.`a1`) and (<cache>(`test`.`t2`.`b2`) = `test`.`t3a`.`c2`))))) or <expr_cache><`test`.`t2`.`b2`>(<in_optimizer>(`test`.`t2`.`b2`,`test`.`t2`.`b2` in ( <materialize> (select `test`.`t3b`.`c2` from `test`.`t3` `t3b` where (`test`.`t3b`.`c2` like '%03') ), <primary_index_lookup>(`test`.`t2`.`b2` in <temporary table> on distinct_key where ((`test`.`t2`.`b2` = `materialized subselect`.`c2`))))))) and (<cache>(`test`.`t1`.`a1`) = `test`.`t2`.`b1`) and (<cache>(`test`.`t1`.`a2`) = `test`.`t2`.`b2`))))) and <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`,`test`.`t1`.`a2`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select `test`.`t3c`.`c1`,`test`.`t3c`.`c2` from `test`.`t3` `t3c` where (<expr_cache><`test`.`t3c`.`c2`,`test`.`t3c`.`c1`,`test`.`t1`.`a2`>(<in_optimizer>((`test`.`t3c`.`c1`,`test`.`t3c`.`c2`),<exists>(<index_lookup>(<cache>(`test`.`t3c`.`c1`) in t2i on it2i3 where (((`test`.`t2i`.`b2` > '0') or (`test`.`t2i`.`b2` = `test`.`t1`.`a2`)) and (<cache>(`test`.`t3c`.`c1`) = `test`.`t2i`.`b1`) and (<cache>(`test`.`t3c`.`c2`) = `test`.`t2i`.`b2`)))))) and (<cache>(`test`.`t1`.`a1`) = `test`.`t3c`.`c1`) and (<cache>(`test`.`t1`.`a2`) = `test`.`t3c`.`c2`))))))
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where (<expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select `test`.`t2`.`b1`,`test`.`t2`.`b2` from `test`.`t2` where ((<expr_cache><`test`.`t2`.`b2`,`test`.`t1`.`a1`>(<in_optimizer>(`test`.`t2`.`b2`,<exists>(select `test`.`t3a`.`c2` from `test`.`t3` `t3a` where ((`test`.`t3a`.`c1` = `test`.`t1`.`a1`) and (<cache>(`test`.`t2`.`b2`) = `test`.`t3a`.`c2`))))) or <expr_cache><`test`.`t2`.`b2`>(<in_optimizer>(`test`.`t2`.`b2`,`test`.`t2`.`b2` in ( <materialize> (select `test`.`t3b`.`c2` from `test`.`t3` `t3b` where (`test`.`t3b`.`c2` like '%03') ), <primary_index_lookup>(`test`.`t2`.`b2` in <temporary table> on distinct_key where ((`test`.`t2`.`b2` = `materialized subselect`.`c2`))))))) and (<cache>(`test`.`t1`.`a1`) = `test`.`t2`.`b1`) and (<cache>(`test`.`t1`.`a2`) = `test`.`t2`.`b2`))))) and <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`,`test`.`t1`.`a2`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select `test`.`t3c`.`c1`,`test`.`t3c`.`c2` from `test`.`t3` `t3c` where (<expr_cache><`test`.`t3c`.`c2`,`test`.`t3c`.`c1`,`test`.`t1`.`a2`>(<in_optimizer>((`test`.`t3c`.`c1`,`test`.`t3c`.`c2`),<exists>(<index_lookup>(<cache>(`test`.`t3c`.`c1`) in t2i on it2i3 where (((`test`.`t2i`.`b2` > '0') or (`test`.`t2i`.`b2` = `test`.`t1`.`a2`)) and (<cache>(`test`.`t3c`.`c1`) = `test`.`t2i`.`b1`) and (<cache>(`test`.`t3c`.`c2`) = `test`.`t2i`.`b2`)))))) and (<cache>(`test`.`t1`.`a1`) = `test`.`t3c`.`c1`) and (<cache>(`test`.`t1`.`a2`) = `test`.`t3c`.`c2`))))))
 explain extended
 select * from t1 where (a1, a2) in (select '1 - 01', '2 - 01');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select '1 - 01','2 - 01' having ((<cache>(`test`.`t1`.`a1`) = '1 - 01') and (<cache>(`test`.`t1`.`a2`) = '2 - 01')))))
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select '1 - 01','2 - 01' having (((<cache>(`test`.`t1`.`a1`) = '1 - 01') or isnull('1 - 01')) and ((<cache>(`test`.`t1`.`a2`) = '2 - 01') or isnull('2 - 01')) and <is_not_null_test>('1 - 01') and <is_not_null_test>('2 - 01')))))
 select * from t1 where (a1, a2) in (select '1 - 01', '2 - 01');
 a1	a2
 1 - 01	2 - 01
@@ -493,7 +493,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select '1 - 01','2 - 01' having ((<cache>(`test`.`t1`.`a1`) = '1 - 01') and (<cache>(`test`.`t1`.`a2`) = '2 - 01')))))
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><`test`.`t1`.`a2`,`test`.`t1`.`a1`>(<in_optimizer>((`test`.`t1`.`a1`,`test`.`t1`.`a2`),<exists>(select '1 - 01','2 - 01' having (((<cache>(`test`.`t1`.`a1`) = '1 - 01') or isnull('1 - 01')) and ((<cache>(`test`.`t1`.`a2`) = '2 - 01') or isnull('2 - 01')) and <is_not_null_test>('1 - 01') and <is_not_null_test>('2 - 01')))))
 select * from t1 where (a1, a2) in (select '1 - 01', '2 - 01' from dual);
 a1	a2
 1 - 01	2 - 01
@@ -549,7 +549,7 @@ a1	a2
 Test that BLOBs are not materialized (except when arguments of some functions).
 */
 # force materialization to be always considered
-set @@optimizer_switch='semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 set @prefix_len = 6;
 set @blob_len = 16;
 set @suffix_len = @blob_len - @prefix_len;
@@ -583,7 +583,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_16	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 2	DEPENDENT SUBQUERY	t2_16	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
-Note	1003	select left(`test`.`t1_16`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_16`.`a2`,7) AS `left(a2,7)` from `test`.`t1_16` where <expr_cache><`test`.`t1_16`.`a1`>(<in_optimizer>(`test`.`t1_16`.`a1`,<exists>(select 1 from `test`.`t2_16` where ((`test`.`t2_16`.`b1` > '0') and (<cache>(`test`.`t1_16`.`a1`) = `test`.`t2_16`.`b1`)))))
+Note	1003	select left(`test`.`t1_16`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_16`.`a2`,7) AS `left(a2,7)` from `test`.`t1_16` where <expr_cache><`test`.`t1_16`.`a1`>(<in_optimizer>(`test`.`t1_16`.`a1`,<exists>(select `test`.`t2_16`.`b1` from `test`.`t2_16` where ((`test`.`t2_16`.`b1` > '0') and (<cache>(`test`.`t1_16`.`a1`) = `test`.`t2_16`.`b1`)))))
 select left(a1,7), left(a2,7)
 from t1_16
 where a1 in (select b1 from t2_16 where b1 > '0');
@@ -662,7 +662,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Using join buffer (flat, BNL join)
 4	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><concat(`test`.`t1`.`a1`,'x')>(<in_optimizer>(concat(`test`.`t1`.`a1`,'x'),<exists>(select 1 from `test`.`t1_16` where (<expr_cache><`test`.`t1_16`.`a2`,`test`.`t1_16`.`a1`>(<in_optimizer>((`test`.`t1_16`.`a1`,`test`.`t1_16`.`a2`),<exists>(select `test`.`t2_16`.`b1`,`test`.`t2_16`.`b2` from `test`.`t2_16` join `test`.`t2` where ((`test`.`t2`.`b2` = substr(`test`.`t2_16`.`b2`,1,6)) and <expr_cache><`test`.`t2`.`b1`>(<in_optimizer>(`test`.`t2`.`b1`,`test`.`t2`.`b1` in ( <materialize> (select `test`.`t3`.`c1` from `test`.`t3` where (`test`.`t3`.`c2` > '0') ), <primary_index_lookup>(`test`.`t2`.`b1` in <temporary table> on distinct_key where ((`test`.`t2`.`b1` = `materialized subselect`.`c1`)))))) and (<cache>(`test`.`t1_16`.`a1`) = `test`.`t2_16`.`b1`) and (<cache>(`test`.`t1_16`.`a2`) = `test`.`t2_16`.`b2`))))) and (<cache>(concat(`test`.`t1`.`a1`,'x')) = left(`test`.`t1_16`.`a1`,8))))))
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where <expr_cache><concat(`test`.`t1`.`a1`,'x')>(<in_optimizer>(concat(`test`.`t1`.`a1`,'x'),<exists>(select left(`test`.`t1_16`.`a1`,8) from `test`.`t1_16` where (<expr_cache><`test`.`t1_16`.`a2`,`test`.`t1_16`.`a1`>(<in_optimizer>((`test`.`t1_16`.`a1`,`test`.`t1_16`.`a2`),<exists>(select `test`.`t2_16`.`b1`,`test`.`t2_16`.`b2` from `test`.`t2_16` join `test`.`t2` where ((`test`.`t2`.`b2` = substr(`test`.`t2_16`.`b2`,1,6)) and <expr_cache><`test`.`t2`.`b1`>(<in_optimizer>(`test`.`t2`.`b1`,`test`.`t2`.`b1` in ( <materialize> (select `test`.`t3`.`c1` from `test`.`t3` where (`test`.`t3`.`c2` > '0') ), <primary_index_lookup>(`test`.`t2`.`b1` in <temporary table> on distinct_key where ((`test`.`t2`.`b1` = `materialized subselect`.`c1`)))))) and (<cache>(`test`.`t1_16`.`a1`) = `test`.`t2_16`.`b1`) and (<cache>(`test`.`t1_16`.`a2`) = `test`.`t2_16`.`b2`))))) and (<cache>(concat(`test`.`t1`.`a1`,'x')) = left(`test`.`t1_16`.`a1`,8))))))
 drop table t1_16, t2_16, t3_16;
 set @blob_len = 512;
 set @suffix_len = @blob_len - @prefix_len;
@@ -696,7 +696,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_512	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 2	DEPENDENT SUBQUERY	t2_512	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
-Note	1003	select left(`test`.`t1_512`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_512`.`a2`,7) AS `left(a2,7)` from `test`.`t1_512` where <expr_cache><`test`.`t1_512`.`a1`>(<in_optimizer>(`test`.`t1_512`.`a1`,<exists>(select 1 from `test`.`t2_512` where ((`test`.`t2_512`.`b1` > '0') and (<cache>(`test`.`t1_512`.`a1`) = `test`.`t2_512`.`b1`)))))
+Note	1003	select left(`test`.`t1_512`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_512`.`a2`,7) AS `left(a2,7)` from `test`.`t1_512` where <expr_cache><`test`.`t1_512`.`a1`>(<in_optimizer>(`test`.`t1_512`.`a1`,<exists>(select `test`.`t2_512`.`b1` from `test`.`t2_512` where ((`test`.`t2_512`.`b1` > '0') and (<cache>(`test`.`t1_512`.`a1`) = `test`.`t2_512`.`b1`)))))
 select left(a1,7), left(a2,7)
 from t1_512
 where a1 in (select b1 from t2_512 where b1 > '0');
@@ -789,7 +789,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
-Note	1003	select left(`test`.`t1_1024`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1024`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1024` where <expr_cache><`test`.`t1_1024`.`a1`>(<in_optimizer>(`test`.`t1_1024`.`a1`,<exists>(select 1 from `test`.`t2_1024` where ((`test`.`t2_1024`.`b1` > '0') and (<cache>(`test`.`t1_1024`.`a1`) = `test`.`t2_1024`.`b1`)))))
+Note	1003	select left(`test`.`t1_1024`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1024`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1024` where <expr_cache><`test`.`t1_1024`.`a1`>(<in_optimizer>(`test`.`t1_1024`.`a1`,<exists>(select `test`.`t2_1024`.`b1` from `test`.`t2_1024` where ((`test`.`t2_1024`.`b1` > '0') and (<cache>(`test`.`t1_1024`.`a1`) = `test`.`t2_1024`.`b1`)))))
 select left(a1,7), left(a2,7)
 from t1_1024
 where a1 in (select b1 from t2_1024 where b1 > '0');
@@ -817,7 +817,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
-Note	1003	select left(`test`.`t1_1024`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1024`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1024` where <expr_cache><`test`.`t1_1024`.`a1`>(<in_optimizer>(`test`.`t1_1024`.`a1`,`test`.`t1_1024`.`a1` in (select 1 from `test`.`t2_1024` where ((`test`.`t2_1024`.`b1` > '0') and (<cache>(`test`.`t1_1024`.`a1`) = substr(`test`.`t2_1024`.`b1`,1,1024))))))
+Note	1003	select left(`test`.`t1_1024`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1024`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1024` where <expr_cache><`test`.`t1_1024`.`a1`>(<in_optimizer>(`test`.`t1_1024`.`a1`,<exists>(select substr(`test`.`t2_1024`.`b1`,1,1024) from `test`.`t2_1024` where ((`test`.`t2_1024`.`b1` > '0') and (<cache>(`test`.`t1_1024`.`a1`) = substr(`test`.`t2_1024`.`b1`,1,1024))))))
 select left(a1,7), left(a2,7)
 from t1_1024
 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0');
@@ -882,7 +882,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_1025	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 2	DEPENDENT SUBQUERY	t2_1025	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
-Note	1003	select left(`test`.`t1_1025`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1025`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1025` where <expr_cache><`test`.`t1_1025`.`a1`>(<in_optimizer>(`test`.`t1_1025`.`a1`,<exists>(select 1 from `test`.`t2_1025` where ((`test`.`t2_1025`.`b1` > '0') and (<cache>(`test`.`t1_1025`.`a1`) = `test`.`t2_1025`.`b1`)))))
+Note	1003	select left(`test`.`t1_1025`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1025`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1025` where <expr_cache><`test`.`t1_1025`.`a1`>(<in_optimizer>(`test`.`t1_1025`.`a1`,<exists>(select `test`.`t2_1025`.`b1` from `test`.`t2_1025` where ((`test`.`t2_1025`.`b1` > '0') and (<cache>(`test`.`t1_1025`.`a1`) = `test`.`t2_1025`.`b1`)))))
 select left(a1,7), left(a2,7)
 from t1_1025
 where a1 in (select b1 from t2_1025 where b1 > '0');
@@ -910,7 +910,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_1025	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 2	DEPENDENT SUBQUERY	t2_1025	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
-Note	1003	select left(`test`.`t1_1025`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1025`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1025` where <expr_cache><`test`.`t1_1025`.`a1`>(<in_optimizer>(`test`.`t1_1025`.`a1`,`test`.`t1_1025`.`a1` in (select 1 from `test`.`t2_1025` where ((`test`.`t2_1025`.`b1` > '0') and (<cache>(`test`.`t1_1025`.`a1`) = substr(`test`.`t2_1025`.`b1`,1,1025))))))
+Note	1003	select left(`test`.`t1_1025`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1025`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1025` where <expr_cache><`test`.`t1_1025`.`a1`>(<in_optimizer>(`test`.`t1_1025`.`a1`,<exists>(select substr(`test`.`t2_1025`.`b1`,1,1025) from `test`.`t2_1025` where ((`test`.`t2_1025`.`b1` > '0') and (<cache>(`test`.`t1_1025`.`a1`) = substr(`test`.`t2_1025`.`b1`,1,1025))))))
 select left(a1,7), left(a2,7)
 from t1_1025
 where a1 in (select substring(b1,1,1025) from t2_1025 where b1 > '0');
@@ -951,7 +951,7 @@ insert into t1bit values (b'010', b'110');
 insert into t2bit values (b'001', b'101');
 insert into t2bit values (b'010', b'110');
 insert into t2bit values (b'110', b'111');
-set @@optimizer_switch='semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 explain extended select bin(a1), bin(a2)
 from t1bit
 where (a1, a2) in (select b1, b2 from t2bit);
@@ -994,7 +994,7 @@ drop table t1, t2, t3, t1i, t2i, t3i, columns;
 /******************************************************************************
 * Test the cache of the left operand of IN.
 ******************************************************************************/
-set @@optimizer_switch='semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 create table t1 (s1 int);
 create table t2 (s2 int);
 insert into t1 values (5),(1),(0);
@@ -1097,7 +1097,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` group by `test`.`t1`.`a` having <expr_cache><`test`.`t1`.`a`,max(`test`.`t1`.`b`)>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t2` where (<nop>(<expr_cache><`test`.`t2`.`d`,max(`test`.`t1`.`b`)>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where (max(`test`.`t1`.`b`) = `test`.`t3`.`e`) having (<cache>(`test`.`t2`.`d`) >= <ref_null_helper>(`test`.`t3`.`e`)))))) and (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`c`)))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` group by `test`.`t1`.`a` having <expr_cache><`test`.`t1`.`a`,max(`test`.`t1`.`b`)>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`c` from `test`.`t2` where (<nop>(<expr_cache><`test`.`t2`.`d`,max(`test`.`t1`.`b`)>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where (max(`test`.`t1`.`b`) = `test`.`t3`.`e`) having (<cache>(`test`.`t2`.`d`) >= <ref_null_helper>(`test`.`t3`.`e`)))))) and (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`c`)))))
 select a from t1 group by a
 having a in (select c from t2 where d >= some(select e from t3 where max(b)=e));
 a
@@ -1112,7 +1112,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where <expr_cache><`test`.`t1`.`a`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t2` where (<nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select 1 from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))) and (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`c`)))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where <expr_cache><`test`.`t1`.`a`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`c` from `test`.`t2` where (<nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))) and (<cache>(`test`.`t1`.`a`) = `test`.`t2`.`c`)))))
 select a from t1
 where a in (select c from t2 where d >= some(select e from t3 where b=e));
 a
@@ -1136,27 +1136,36 @@ drop table t2;
 create table t1 (a1 int key);
 create table t2 (b1 int);
 insert into t1 values (5);
+Only the last query returns correct result. Filed as BUG#40037.
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 explain select min(a1) from t1 where 7 in (select b1 from t2 group by b1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	const row not found
 select min(a1) from t1 where 7 in (select b1 from t2 group by b1);
 min(a1)
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
 explain select min(a1) from t1 where 7 in (select b1 from t2 group by b1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
 2	DEPENDENT SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	const row not found
 select min(a1) from t1 where 7 in (select b1 from t2 group by b1);
 min(a1)
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 explain select min(a1) from t1 where 7 in (select b1 from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	const row not found
 select min(a1) from t1 where 7 in (select b1 from t2);
 min(a1)
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
+explain select min(a1) from t1 where 7 in (select b1 from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select min(a1) from t1 where 7 in (select b1 from t2);
+min(a1)
+set @@optimizer_switch='materialization=off,in_to_exists=off,semijoin=on';
 explain select min(a1) from t1 where 7 in (select b1 from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
@@ -1167,7 +1176,7 @@ drop table t1,t2;
 create table t1 (a char(2), b varchar(10));
 insert into t1 values ('a',  'aaa');
 insert into t1 values ('aa', 'aaaa');
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 explain select a,b from t1 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
@@ -1187,7 +1196,7 @@ INSERT INTO t1 (f1, f2) VALUES (10, 1.668);
 CREATE TABLE t2 LIKE t1;
 INSERT INTO t2 VALUES (1, 1.789);
 INSERT INTO t2 VALUES (13, 1.454);
-SET @@optimizer_switch='default,semijoin=on,materialization=on';
+SET @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=on';
 EXPLAIN SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	2	
@@ -1208,7 +1217,7 @@ PRIMARY KEY (pk)
 INSERT INTO t1 VALUES (1,'o','ffff','ffff','ffoo'),(2,'f','ffff','ffff','ffff');
 CREATE TABLE t2 LIKE t1;
 INSERT INTO t2 VALUES (1,'i','iiii','iiii','iiii'),(2,'f','ffff','ffff','ffff');
-SET @@optimizer_switch='default,semijoin=on,materialization=on';
+SET @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=on';
 EXPLAIN SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
@@ -1237,7 +1246,7 @@ i
 3
 4
 set @save_optimizer_switch=@@optimizer_switch;
-set session optimizer_switch='materialization=off';
+set session optimizer_switch='materialization=off,in_to_exists=on';
 select * from t1 where t1.i in (select t2.i from t2 join t3 where t2.i + t3.i = 5);
 i
 1
@@ -1380,34 +1389,41 @@ INSERT IGNORE INTO t1 VALUES (1,1),(2,2);
 CREATE TABLE t2 ( f2 int);
 INSERT IGNORE INTO t2 VALUES (3),(4);
 CREATE TABLE t3 (f3a int, f3b int);
-set session optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off';
+set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,in_to_exists=off';
 EXPLAIN
 SELECT * FROM t2 WHERE (SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
 3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	SUBQUERY	t3	system	NULL	NULL	NULL	NULL	0	const row not found
 SELECT * FROM t2 WHERE (SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1);
 f2
 EXPLAIN
+SELECT (SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	SUBQUERY	t3	system	NULL	NULL	NULL	NULL	0	const row not found
+SELECT (SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1);
+(SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1)
+NULL
+EXPLAIN
 SELECT * FROM t2 WHERE (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
 3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
 2	SUBQUERY	t3	system	NULL	NULL	NULL	NULL	0	const row not found
 SELECT * FROM t2 WHERE (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
 f2
-insert into t3 values (1,1),(2,2);
 EXPLAIN
-SELECT * FROM t2 WHERE (SELECT f3a FROM t3 where f3a > 3) NOT IN (SELECT f1a FROM t1);
+SELECT (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
-3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
-2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
-SELECT * FROM t2 WHERE (SELECT f3a FROM t3 where f3a > 3) NOT IN (SELECT f1a FROM t1);
-f2
-3
-4
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	SUBQUERY	t3	system	NULL	NULL	NULL	NULL	0	const row not found
+SELECT (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
+(SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1)
+NULL
 drop table t1, t2, t3;
 #
 # LPBUG#730604 Assertion `bit < (map)->n_bits' failed in maria-5.3 with
@@ -1417,7 +1433,7 @@ CREATE TABLE t1 (f1 int NOT NULL, f2 int, f3 int) ;
 CREATE TABLE t2 (f1 int NOT NULL, f2 int, f3 int) ;
 INSERT INTO t1 VALUES (60, 3, null), (61, null, 77);
 INSERT INTO t2 VALUES (1000,6,2);
-set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off';
+set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,in_to_exists=off';
 EXPLAIN
 SELECT (f1, f2, f3) NOT IN
 (SELECT COUNT(DISTINCT f2), f1, f3 FROM t1 GROUP BY f1, f3)
diff --git a/mysql-test/r/subselect_mat_cost.result b/mysql-test/r/subselect_mat_cost.result
new file mode 100644
index 00000000000..9d6986cf092
--- /dev/null
+++ b/mysql-test/r/subselect_mat_cost.result
@@ -0,0 +1,3771 @@
+drop table if exists t1, t2, t1_1024, t2_1024;
+drop procedure if exists make_t1_indexes;
+drop procedure if exists make_t2_indexes;
+drop procedure if exists remove_t1_indexes;
+drop procedure if exists remove_t2_indexes;
+drop procedure if exists add_materialization_data;
+drop procedure if exists delete_materialization_data;
+drop procedure if exists set_all_columns_not_null;
+drop procedure if exists set_all_columns_nullable;
+create table t1 (a1 char(8), a2 char(8), a3 char(8), a4 int);
+insert into t1 values ('1 - 00', '2 - 00', '3 - 00', 0);
+insert into t1 values ('1 - 01', '2 - 01', '3 - 01', 1);
+insert into t1 values ('1 - 02', '2 - 02', '3 - 02', 2);
+create table t2 (b1 char(8), b2 char(8), b3 char(8), b4 int);
+insert into t2 values ('1 - 01', '2 - 01', '3 - 01', 1);
+insert into t2 values ('1 - 01', '2 - 01', '3 - 02', 2);
+insert into t2 values ('1 - 02', '2 - 02', '3 - 03', 3);
+insert into t2 values ('1 - 02', '2 - 02', '3 - 04', 4);
+insert into t2 values ('1 - 03', '2 - 03', '3 - 05', 5);
+create table t1_1024 (a1 blob(1024), a2 blob(1024));
+insert into t1_1024 values (concat('1 - 00', repeat('x', 1018)), concat('2 - 00', repeat('x', 1018)));
+insert into t1_1024 values (concat('1 - 01', repeat('x', 1018)), concat('2 - 01', repeat('x', 1018)));
+create table t2_1024 (b1 blob(1024), b2 blob(1024));
+insert into t2_1024 values (concat('1 - 01', repeat('x', 1018)), concat('2 - 01', repeat('x', 1018)));
+insert into t2_1024 values (concat('1 - 02', repeat('x', 1018)), concat('2 - 02', repeat('x', 1018)));
+insert into t2_1024 values (concat('1 - 03', repeat('x', 1018)), concat('2 - 03', repeat('x', 1018)));
+insert into t2_1024 values (concat('1 - 04', repeat('x', 1018)), concat('2 - 04', repeat('x', 1018)));
+create procedure make_t1_indexes()
+begin
+create index it1i1 on t1 (a1);
+create index it1i2 on t1 (a2);
+create index it1i3 on t1 (a1, a2);
+create index it1_1024i1 on t1_1024 (a1(6));
+create index it1_1024i2 on t1_1024 (a2(6));
+create index it1_1024i3 on t1_1024 (a1(6), a2(6));
+end|
+create procedure make_t2_indexes()
+begin
+create index it2i1 on t2 (b1);
+create index it2i2 on t2 (b2);
+create index it2i3 on t2 (b1, b2);
+create unique index it2i4 on t2 (b1, b2, b3);
+create index it2_1024i1 on t2_1024 (b1(6));
+create index it2_1024i2 on t2_1024 (b2(6));
+create index it2_1024i3 on t2_1024 (b1(6), b2(6));
+end|
+create procedure remove_t1_indexes()
+begin
+drop index it1i1 on t1;
+drop index it1i2 on t1;
+drop index it1i3 on t1;
+drop index it1_1024i1 on t1_1024;
+drop index it1_1024i2 on t1_1024;
+drop index it1_1024i3 on t1_1024;
+end|
+create procedure remove_t2_indexes()
+begin
+drop index it2i1 on t2;
+drop index it2i2 on t2;
+drop index it2i3 on t2;
+drop index it2i4 on t2;
+drop index it2_1024i1 on t2_1024;
+drop index it2_1024i2 on t2_1024;
+drop index it2_1024i3 on t2_1024;
+end|
+create procedure add_materialization_data()
+begin
+insert into t1 values ('1 - 03', '2 - 03', '3 - 03', 3);
+insert into t1 values ('1 - 04', '2 - 04', '3 - 04', 4);
+insert into t1 values ('1 - 05', '2 - 05', '3 - 05', 5);
+insert into t1 values ('1 - 06', '2 - 06', '3 - 06', 6);
+insert into t1 values ('1 - 07', '2 - 07', '3 - 07', 7);
+insert into t1_1024 values (concat('1 - 03', repeat('x', 1018)), concat('2 - 03', repeat('x', 1018)));
+end|
+create procedure delete_materialization_data()
+begin
+delete from t1 where a1 >= '1 - 03';
+delete from t1_1024 where a1 >= '1 - 03';
+end|
+create procedure set_all_columns_not_null()
+begin
+alter table t1 modify a1 char(8) not null, modify a2 char(8) not null, modify a3 char(8) not null;
+alter table t2 modify b1 char(8) not null, modify b2 char(8) not null, modify b3 char(8) not null;
+end|
+create procedure set_all_columns_nullable()
+begin
+alter table t1 modify a1 char(8) null, modify a2 char(8) null, modify a3 char(8) null;
+alter table t2 modify b1 char(8) null, modify b2 char(8) null, modify b3 char(8) null;
+end|
+
+/******************************************************************************
+1. Both materialization and in-to-exists are ON, make a cost-based choice.
+******************************************************************************/
+set @@optimizer_switch='materialization=on,in_to_exists=on';
+
+/* 1.1 In-to-exists is cheaper */
+call make_t1_indexes();
+/* 1.1.1 non-indexed table access */
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i2	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+3	DEPENDENT UNION	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ref	it1i1,it1i3	it1i1	9	const	1	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i1,it1i2,it1i3	it1i3	18	NULL	3	Using where; Using index
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+/* 1.1.2 indexed table access, nullabale columns. */
+call make_t2_indexes();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	9	func	2	Using index; Using where; Full scan on NULL key
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i3	9	func	2	Using index; Using where; Full scan on NULL key
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i3	9	func	2	Using index; Using where; Full scan on NULL key
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i2	it2i2	9	func	2	Using index
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i4	18	func,func	1	Using index; Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i2	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	9	func	2	Using index
+3	DEPENDENT UNION	t3	index	NULL	it2i4	27	NULL	5	Using where; Using index
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ref	it1i1,it1i3	it1i1	9	const	1	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	9	const	1	Using index condition
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i4	18	func,func	1	Using index; Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	9	NULL	1	Using where; Using index
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	1	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	1	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	NULL	it2i4	27	NULL	1	Using index
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	NULL	it2i4	27	NULL	1	Using where; Using index
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i4	27	NULL	2	Using where; Using index for group-by
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i3	it2_1024i3	9	func	1	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i2,it2_1024i3	it2_1024i1	9	func	2	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	9	const	2	Using index; Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i1,it1i2,it1i3	it1i3	18	NULL	3	Using where; Using index
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+/* 1.1.3 indexed table access, non-nullabale columns. */
+call set_all_columns_not_null();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	8	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i4	8	func	1	Using index; Using where
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	16	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	ref	it2i4,it2i1,it2i2,it2i3	it2i4	8	func	2	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	16	NULL	3	Using index
+2	DEPENDENT SUBQUERY	t2	ref	it2i4,it2i1,it2i2,it2i3	it2i4	8	func	2	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	16	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i2	it2i2	8	func	2	Using index
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	16	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i4	16	func,func	1	Using index; Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i2	8	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	8	func	2	Using index
+3	DEPENDENT UNION	t3	index	NULL	it2i4	24	NULL	5	Using where; Using index
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ref	it1i1,it1i3	it1i1	8	const	1	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	8	const	1	Using index condition
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	16	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i4	16	func,func	1	Using index; Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	8	NULL	1	Using where; Using index
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	1	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	1	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	NULL	it2i4	24	NULL	1	Using index
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	index	NULL	it2i4	24	NULL	1	Using where; Using index
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i4	24	NULL	2	Using where; Using index for group-by
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i3	it2_1024i3	9	func	1	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i2,it2_1024i3	it2_1024i1	9	func	2	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	8	const	5	Using index; Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i1,it1i2,it1i3	it1i3	16	NULL	3	Using where; Using index
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	8	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	16	NULL	3	Using where; Using index
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	8	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	8	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+call set_all_columns_nullable();
+
+/* 1.2 Materialization is cheaper */
+call add_materialization_data();
+call remove_t1_indexes();
+/* 1.2.1 non-indexed table access */
+call remove_t2_indexes();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+1 - 03	1
+1 - 04	0
+1 - 05	0
+1 - 06	0
+1 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+1 - 04	2 - 04
+1 - 05	2 - 05
+1 - 06	2 - 06
+1 - 07	2 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+3	DEPENDENT UNION	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+2 - 03
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+1 - 03
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+1 - 03
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+/* 1.2.2 indexed table access, nullabale columns. */
+call make_t2_indexes();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	9	NULL	5	Using where; Using index
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+1 - 03	1
+1 - 04	0
+1 - 05	0
+1 - 06	0
+1 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i2,it2i3	it2i3	18	NULL	5	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	range	it2i4,it2i1,it2i2,it2i3	it2i3	9	NULL	4	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i2	it2i2	9	NULL	5	Using index
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i2,it2i3	it2i3	18	NULL	5	Using where; Using index
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+1 - 04	2 - 04
+1 - 05	2 - 05
+1 - 06	2 - 06
+1 - 07	2 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	9	func	2	Using index
+3	DEPENDENT UNION	t3	index	NULL	it2i4	27	NULL	5	Using where; Using index
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+2 - 03
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ref	it2i2	it2i2	9	const	1	Using index condition
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i2,it2i3	it2i4	27	NULL	5	Using index
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	9	NULL	5	Using where; Using index
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	5	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	5	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	range	NULL	it2i4	27	NULL	6	Using index for group-by
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	range	NULL	it2i4	27	NULL	6	Using where; Using index for group-by
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i4	27	NULL	2	Using where; Using index for group-by
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i3	it2_1024i3	9	func	1	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i2,it2_1024i3	it2_1024i1	9	func	2	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	9	const	2	Using index; Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+1 - 03
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+1 - 03
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+/* 1.2.3 indexed table access, non-nullabale columns. */
+call set_all_columns_not_null();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	8	NULL	5	Using where; Using index
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+1 - 03	1
+1 - 04	0
+1 - 05	0
+1 - 06	0
+1 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i2,it2i3	it2i3	16	NULL	5	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	SUBQUERY	t2	range	it2i4,it2i1,it2i2,it2i3	it2i3	8	NULL	4	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i2	it2i2	8	NULL	5	Using index
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i2,it2i3	it2i3	16	NULL	5	Using where; Using index
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+1 - 04	2 - 04
+1 - 05	2 - 05
+1 - 06	2 - 06
+1 - 07	2 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	8	func	2	Using index
+3	DEPENDENT UNION	t3	index	NULL	it2i4	24	NULL	5	Using where; Using index
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+2 - 03
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	ref	it2i2	it2i2	8	const	1	Using index condition
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i2,it2i3	it2i4	24	NULL	5	Using index
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	8	NULL	5	Using where; Using index
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	5	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	5	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	range	NULL	it2i4	24	NULL	6	Using index for group-by
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	range	NULL	it2i4	24	NULL	6	Using where; Using index for group-by
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i4	24	NULL	2	Using where; Using index for group-by
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i3	it2_1024i3	9	func	1	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i2,it2_1024i3	it2_1024i1	9	func	2	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	8	const	5	Using index; Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+1 - 03
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+1 - 03
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+call set_all_columns_nullable();
+/******************************************************************************
+2. Materialization is OFF, in-to-exists is ON, materialization is cheaper.
+******************************************************************************/
+set @@optimizer_switch='materialization=off,in_to_exists=on';
+/* 2.1 non-indexed table access */
+call remove_t2_indexes();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+1 - 03	1
+1 - 04	0
+1 - 05	0
+1 - 06	0
+1 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+1 - 04	2 - 04
+1 - 05	2 - 05
+1 - 06	2 - 06
+1 - 07	2 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+3	DEPENDENT UNION	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+2 - 03
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+1 - 03
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+1 - 03
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+/* 2.2 indexed table access, nullabale columns. */
+call make_t2_indexes();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	9	func	2	Using index; Using where; Full scan on NULL key
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+1 - 03	1
+1 - 04	0
+1 - 05	0
+1 - 06	0
+1 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i3	9	func	2	Using index; Using where; Full scan on NULL key
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i3	9	func	2	Using index; Using where; Full scan on NULL key
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i2	it2i2	9	func	2	Using index
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i4	18	func,func	1	Using index; Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+1 - 04	2 - 04
+1 - 05	2 - 05
+1 - 06	2 - 06
+1 - 07	2 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	9	func	2	Using index
+3	DEPENDENT UNION	t3	index	NULL	it2i4	27	NULL	5	Using where; Using index
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+2 - 03
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	9	const	1	Using index condition
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i4	18	func,func	1	Using index; Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	9	NULL	1	Using where; Using index
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	1	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	1	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	NULL	it2i4	27	NULL	1	Using index
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	NULL	it2i4	27	NULL	1	Using where; Using index
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i4	27	NULL	2	Using where; Using index for group-by
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i3	it2_1024i3	9	func	1	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i2,it2_1024i3	it2_1024i1	9	func	2	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	9	const	2	Using index; Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+1 - 03
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+1 - 03
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+/* 2.3 indexed table access, non-nullabale columns. */
+call set_all_columns_not_null();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i4	8	func	1	Using index; Using where
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+1 - 03	1
+1 - 04	0
+1 - 05	0
+1 - 06	0
+1 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	ref	it2i4,it2i1,it2i2,it2i3	it2i4	8	func	2	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	
+2	DEPENDENT SUBQUERY	t2	ref	it2i4,it2i1,it2i2,it2i3	it2i4	8	func	2	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+1 - 03	2 - 03	1
+1 - 04	2 - 04	0
+1 - 05	2 - 05	0
+1 - 06	2 - 06	0
+1 - 07	2 - 07	0
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i2	it2i2	8	func	2	Using index
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i4	16	func,func	1	Using index; Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+1 - 04	2 - 04
+1 - 05	2 - 05
+1 - 06	2 - 06
+1 - 07	2 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	8	func	2	Using index
+3	DEPENDENT UNION	t3	index	NULL	it2i4	24	NULL	5	Using where; Using index
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+2 - 03
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	8	const	1	Using index condition
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i2,it2i3	it2i4	16	func,func	1	Using index; Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+1 - 03	2 - 03
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	8	NULL	1	Using where; Using index
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	1	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	1	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+1 - 03	2 - 03	3 - 03	3
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	NULL	it2i4	24	NULL	1	Using index
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	index	NULL	it2i4	24	NULL	1	Using where; Using index
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i4	24	NULL	2	Using where; Using index for group-by
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i3	it2_1024i3	9	func	1	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i2,it2_1024i3	it2_1024i1	9	func	2	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+1 - 03x	2 - 03x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	8	const	5	Using index; Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+1 - 03
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+1 - 03
+1 - 04
+1 - 05
+1 - 06
+1 - 07
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+1 - 03
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+call set_all_columns_nullable();
+/******************************************************************************
+3. Materialization is ON, in-to-exists is OFF, in-to-exists is cheaper.
+******************************************************************************/
+set @@optimizer_switch='materialization=on,in_to_exists=off';
+call delete_materialization_data();
+call make_t1_indexes();
+/* 3.1 non-indexed table access */
+call remove_t2_indexes();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i2	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+3	DEPENDENT UNION	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ref	it1i1,it1i3	it1i1	9	const	1	Using where; Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where; Using temporary; Using filesort
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i1,it1i2,it1i3	it1i3	18	NULL	3	Using where; Using index
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+/* 3.2 indexed table access, nullabale columns. */
+call make_t2_indexes();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using index
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	9	NULL	5	Using where; Using index
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using index
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	5	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using index
+2	SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i3	9	NULL	4	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	t2	index	NULL	it2i2	9	NULL	5	Using index
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	5	Using where; Using index
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i2	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	9	func	2	Using index
+3	DEPENDENT UNION	t3	index	NULL	it2i4	27	NULL	5	Using where; Using index
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ref	it1i1,it1i3	it1i1	9	const	1	Using where; Using index
+2	SUBQUERY	t2	ref	it2i2	it2i2	9	const	1	Using index condition
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	t2	index	NULL	it2i4	27	NULL	5	Using index
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	9	NULL	5	Using where; Using index
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	5	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	18	NULL	5	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	range	NULL	it2i4	27	NULL	6	Using index for group-by
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	range	NULL	it2i4	27	NULL	6	Using where; Using index for group-by
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i4	27	NULL	2	Using where; Using index for group-by
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i3	it2_1024i3	9	func	1	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i2,it2_1024i3	it2_1024i1	9	func	2	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	9	const	2	Using index; Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i1,it1i2,it1i3	it1i3	18	NULL	3	Using where; Using index
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	18	NULL	3	Using where; Using index
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	9	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+/* 3.3 indexed table access, non-nullabale columns. */
+call set_all_columns_not_null();
+
+/* A. Subqueries in the SELECT clause. */
+explain
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	8	NULL	3	Using index
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	8	NULL	5	Using where; Using index
+select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
+a1	a1 in (select b1 from t2 where b1 > '0')
+1 - 00	0
+1 - 01	1
+1 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	16	NULL	3	Using index
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	5	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+explain
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	16	NULL	3	Using index
+2	SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i3	8	NULL	4	Using where; Using index
+select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
+a1	a2	(a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
+1 - 00	2 - 00	0
+1 - 01	2 - 01	1
+1 - 02	2 - 02	1
+
+/*
+B. "Natural" examples of subqueries without grouping that
+cannot be flattened into semijoin.
+*/
+explain
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	16	NULL	3	Using where; Using index
+2	SUBQUERY	t2	index	NULL	it2i2	8	NULL	5	Using index
+select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	16	NULL	3	Using where; Using index
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	5	Using where; Using index
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
+a1	a2
+1 - 00	2 - 00
+1 - 01	2 - 01
+1 - 02	2 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i2	8	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	t2	ref	it2i2	it2i2	8	func	2	Using index
+3	DEPENDENT UNION	t3	index	NULL	it2i4	24	NULL	5	Using where; Using index
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
+a2
+2 - 01
+2 - 02
+
+explain
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ref	it1i1,it1i3	it1i1	8	const	1	Using where; Using index
+2	SUBQUERY	t2	ref	it2i2	it2i2	8	const	1	Using index condition
+select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
+a1
+1 - 02
+
+explain
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i3	16	NULL	3	Using where; Using index
+2	SUBQUERY	t2	index	NULL	it2i4	24	NULL	5	Using index
+select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
+a1	a2
+1 - 01	2 - 01
+1 - 02	2 - 02
+
+/* C. Subqueries in the WHERE clause with GROUP BY. */
+explain
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i1	8	NULL	5	Using where; Using index
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	5	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	index	it2i4,it2i1,it2i3	it2i3	16	NULL	5	Using where; Using index
+select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 <  '2 - 04');
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+1 - 02	2 - 02	3 - 02	2
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	range	NULL	it2i4	24	NULL	6	Using index for group-by
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+explain
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	range	NULL	it2i4	24	NULL	6	Using where; Using index for group-by
+select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
+a1	a2	a3	a4
+
+explain
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	range	it2i4,it2i1,it2i3	it2i4	24	NULL	2	Using where; Using index for group-by
+select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
+a1	a2	a3	a4
+1 - 01	2 - 01	3 - 01	1
+
+/*
+D. Subqueries for which materialization is not possible, and the
+optimizer reverts to in-to-exists.
+*/
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i3	it2_1024i3	9	func	1	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	index_subquery	it2_1024i1,it2_1024i2,it2_1024i3	it2_1024i1	9	func	2	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+explain
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+explain
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1_1024	ALL	it1_1024i2	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	t2_1024	range	it2_1024i1,it2_1024i3	it2_1024i1	9	NULL	4	Using where
+select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
+left(a1,7)	left(a2,7)
+1 - 00x	2 - 00x
+1 - 01x	2 - 01x
+
+
+/* E. Edge cases. */
+
+/* E.1 Both materialization and in_to_exists cannot be off. */
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off,in_to_exists=off';
+select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
+ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
+set @@optimizer_switch = @save_optimizer_switch;
+/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	t2	index_subquery	it2i4,it2i1,it2i3	it2i1	8	const	5	Using index; Using where
+select '1 - 03' in (select b1 from t2 where b1 > '0');
+'1 - 03' in (select b1 from t2 where b1 > '0')
+1
+/* E.3 Subqueries without tables. */
+explain
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i1,it1i2,it1i3	it1i3	16	NULL	3	Using where; Using index
+Warnings:
+Note	1249	Select 2 was reduced during optimization
+select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+UNION subqueries are currently limited to only use IN-TO-EXISTS.
+explain
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	8	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
+a1
+1 - 02
+/* E.4 optimize_cond detects FALSE where/having clause. */
+explain
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	it1i2	it1i3	16	NULL	3	Using where; Using index
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
+a1
+1 - 00
+1 - 01
+1 - 02
+/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
+TODO this test produces wrong result due to missing logic to handle the case
+when JOIN::optimize detects an empty subquery result.
+explain
+select a1 from t1 where a1 in (select max(b1) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	8	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select a1 from t1 where a1 in (select max(b1) from t2);
+a1
+
+explain
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	it1i1	8	NULL	3	Using where; Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No matching min/max row
+select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
+a1
+/* E.6 make_join_select detects impossible WHERE. *
+TODO
+/* E.7 constant optimization detects "no matching row in const table". */
+TODO
+/* E.8 Impossible WHERE noticed after reading const tables. */
+explain
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
+'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
+0
+
+/* F. UPDATE/DELETE with subqueries. */
+
+TODO
+
+call set_all_columns_nullable();
+drop procedure make_t1_indexes;
+drop procedure make_t2_indexes;
+drop procedure remove_t1_indexes;
+drop procedure remove_t2_indexes;
+drop procedure add_materialization_data;
+drop procedure delete_materialization_data;
+drop procedure set_all_columns_not_null;
+drop procedure set_all_columns_nullable;
+drop table t1, t2, t1_1024, t2_1024;
diff --git a/mysql-test/r/subselect_mat_cost_bugs.result b/mysql-test/r/subselect_mat_cost_bugs.result
new file mode 100644
index 00000000000..cd0a6c716bb
--- /dev/null
+++ b/mysql-test/r/subselect_mat_cost_bugs.result
@@ -0,0 +1,234 @@
+#
+# LP BUG#643424 valgrind warning in choose_subquery_plan()
+#
+CREATE TABLE t1 (
+pk int(11) NOT NULL AUTO_INCREMENT,
+c1 int(11) DEFAULT NULL,
+c2 int(11) DEFAULT NULL,
+PRIMARY KEY (pk),
+KEY c2 (c2));
+INSERT INTO t1 VALUES (1,NULL,2);
+INSERT INTO t1 VALUES (2,7,9);
+INSERT INTO t1 VALUES (9,NULL,8);
+CREATE TABLE t2 (
+pk int(11) NOT NULL AUTO_INCREMENT,
+c1 int(11) DEFAULT NULL,
+c2 int(11) DEFAULT NULL,
+PRIMARY KEY (pk),
+KEY c2 (c2));
+INSERT INTO t2 VALUES (1,1,7);
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
+SELECT pk FROM t1 WHERE (c2, c1) IN (SELECT c2, c2 FROM t2);
+pk
+set session optimizer_switch=@save_optimizer_switch;
+drop table t1, t2;
+#
+# LP BUG#652727 Crash in create_ref_for_key()
+#
+CREATE TABLE t2 (
+pk int(11) NOT NULL AUTO_INCREMENT,
+c1 int(11) DEFAULT NULL,
+PRIMARY KEY (pk));
+INSERT INTO t2 VALUES (10,7);
+INSERT INTO t2 VALUES (11,1);
+INSERT INTO t2 VALUES (17,NULL);
+CREATE TABLE t1 (
+pk int(11) NOT NULL AUTO_INCREMENT,
+c1 int(11) DEFAULT NULL,
+PRIMARY KEY (pk));
+INSERT INTO t1 VALUES (15,1);
+INSERT INTO t1 VALUES (19,NULL);
+CREATE TABLE t3 (c2 int(11) DEFAULT NULL, KEY c2 (c2));
+INSERT INTO t3 VALUES (1);
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
+SELECT c2
+FROM t3
+WHERE (2, 6) IN (SELECT t1.c1, t1.c1 FROM t1 STRAIGHT_JOIN t2 ON t2.pk = t1.pk);
+c2
+set session optimizer_switch=@save_optimizer_switch;
+drop table t1, t2, t3;
+#
+# LP BUG#641245 Crash in Item_equal::contains
+#
+CREATE TABLE t1 (
+pk int(11) NOT NULL AUTO_INCREMENT,
+c1 int(11) DEFAULT NULL,
+c2 int(11) DEFAULT NULL,
+c3 varchar(1) DEFAULT NULL,
+c4 varchar(1) DEFAULT NULL,
+PRIMARY KEY (pk),
+KEY c2 (c2),
+KEY c3 (c3,c2));
+INSERT INTO t1 VALUES (10,7,8,'v','v');
+INSERT INTO t1 VALUES (11,1,9,'r','r');
+INSERT INTO t1 VALUES (12,5,9,'a','a');
+create table t1a like t1;
+insert into t1a select * from t1;
+create table t1b like t1;
+insert into t1b select * from t1;
+CREATE TABLE t2 (
+pk int(11) NOT NULL AUTO_INCREMENT,
+c1 int(11) DEFAULT NULL,
+c2 int(11) DEFAULT NULL,
+c3 varchar(1) DEFAULT NULL,
+c4 varchar(1) DEFAULT NULL,
+PRIMARY KEY (pk),
+KEY c2 (c2),
+KEY c3 (c3,c2));
+INSERT INTO t2 VALUES (1,NULL,2,'w','w');
+INSERT INTO t2 VALUES (2,7,9,'m','m');
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
+EXPLAIN EXTENDED SELECT pk
+FROM t1
+WHERE c1 IN
+(SELECT t1a.c1
+FROM (t1b JOIN t2 ON t2.c3 = t1b.c4) LEFT JOIN
+t1a ON (t1a.c2 = t1b.pk AND 2)
+WHERE t1.pk) ;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
+2	DEPENDENT SUBQUERY	t2	index	c3	c3	9	NULL	2	100.00	Using index
+2	DEPENDENT SUBQUERY	t1b	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	t1a	ref	c2	c2	5	test.t1b.pk	2	100.00	Using where
+Warnings:
+Note	1276	Field or reference 'test.t1.pk' of SELECT #2 was resolved in SELECT #1
+Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` where <expr_cache><`test`.`t1`.`c1`,`test`.`t1`.`pk`>(<in_optimizer>(`test`.`t1`.`c1`,<exists>(select `test`.`t1a`.`c1` from `test`.`t1b` join `test`.`t2` left join `test`.`t1a` on((2 and (`test`.`t1a`.`c2` = `test`.`t1b`.`pk`))) where (`test`.`t1`.`pk` and (<cache>(`test`.`t1`.`c1`) = `test`.`t1a`.`c1`) and (`test`.`t1b`.`c4` = `test`.`t2`.`c3`)))))
+SELECT pk
+FROM t1
+WHERE c1 IN
+(SELECT t1a.c1
+FROM (t1b JOIN t2 ON t2.c3 = t1b.c4) LEFT JOIN
+t1a ON (t1a.c2 = t1b.pk AND 2)
+WHERE t1.pk) ;
+pk
+DROP TABLE t1, t1a, t1b, t2;
+#
+# LP BUG#714808 Assertion `outer_lookup_keys <= outer_record_count'
+# failed with materialization
+CREATE TABLE t1 ( pk int(11), PRIMARY KEY (pk)) ;
+CREATE TABLE t2 ( f2 int(11)) ;
+CREATE TABLE t3 ( f1 int(11), f3 varchar(1), KEY (f1)) ;
+INSERT INTO t3 VALUES (7,'f');
+set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
+EXPLAIN
+SELECT t1.*
+FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
+WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+SELECT t1.*
+FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
+WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
+pk
+drop table t1,t2,t3;
+#
+# LP BUG#714999 Second crash in select_describe() with nested subqueries
+#
+CREATE TABLE t1 ( pk int(11)) ;
+INSERT INTO t1 VALUES (29);
+CREATE TABLE t2 ( f1 varchar(1)) ;
+INSERT INTO t2 VALUES ('f'),('d');
+CREATE TABLE t3 ( f2 varchar(1)) ;
+EXPLAIN SELECT f2 FROM t3 WHERE (
+SELECT MAX( pk ) FROM t1
+WHERE EXISTS (
+SELECT DISTINCT f1
+FROM t2
+)
+) IS NULL ;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	
+3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using temporary
+drop table t1, t2, t3;
+#
+# LP BUG#715034 Item_sum_distinct::clear(): Assertion `tree != 0' failed
+#
+CREATE TABLE t2 ( f2 int(11)) ;
+CREATE TABLE t1 ( f3 int(11), KEY (f3)) ;
+INSERT INTO t1 VALUES (6),(4);
+EXPLAIN
+SELECT * FROM (SELECT * FROM t2) AS a2
+WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	SUBQUERY	t1	index	NULL	f3	5	NULL	2	Using index
+2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
+insert into t2 values (1),(2);
+EXPLAIN
+SELECT * FROM (SELECT * FROM t2) AS a2
+WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
+3	SUBQUERY	t1	index	NULL	f3	5	NULL	2	Using index
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	
+drop table t1,t2;
+#
+# LP BUG#715027 Assertion `!table || (!table->read_set || bitmap_is_set(table->read_set, field_index))' failed
+#
+CREATE TABLE t1 ( f1 int(11), PRIMARY KEY (f1)) ;
+INSERT INTO t1 VALUES (28),(29);
+CREATE TABLE t2 ( f2 int(11), f3 int(11), f10 varchar(1)) ;
+INSERT INTO t2 VALUES (NULL,6,'f'),(4,2,'d');
+EXPLAIN
+SELECT alias2.f2 AS field1
+FROM t1 AS alias1 JOIN ( SELECT * FROM t2 ) AS alias2 ON alias2.f3 = alias1.f1
+WHERE (
+SELECT t2.f2
+FROM t2 JOIN t1 ON t1.f1
+WHERE t1.f1 AND alias2.f10
+)
+ORDER BY field1 ;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	Using where; Using filesort
+1	PRIMARY	alias1	eq_ref	PRIMARY	PRIMARY	4	alias2.f3	1	Using index
+3	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
+3	DEPENDENT SUBQUERY	t1	index	NULL	PRIMARY	4	NULL	2	Using where; Using index; Using join buffer (flat, BNL join)
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	
+SELECT alias2.f2 AS field1
+FROM t1 AS alias1 JOIN ( SELECT * FROM t2 ) AS alias2 ON alias2.f3 = alias1.f1
+WHERE (
+SELECT t2.f2
+FROM t2 JOIN t1 ON t1.f1
+WHERE t1.f1 AND alias2.f10
+)
+ORDER BY field1 ;
+field1
+drop table t1,t2;
+#
+# LP BUG#718578 Yet another Assertion `!table ||
+# (!table->read_set || bitmap_is_set(table->read_set, field_index))'
+CREATE TABLE t1 ( f1 int(11), f2 int(11), f3 int(11)) ;
+INSERT IGNORE INTO t1 VALUES (28,5,6),(29,NULL,4);
+CREATE TABLE t2 ( f10 varchar(1) );
+INSERT IGNORE INTO t2 VALUES (NULL);
+SELECT f1 AS field1
+FROM ( SELECT * FROM t1 ) AS alias1
+WHERE (SELECT t1.f1
+FROM t2 JOIN t1 ON t1.f2
+WHERE alias1.f3 AND t1.f3) AND f2
+ORDER BY field1;
+field1
+28
+drop table t1,t2;
+#
+# LP BUG#601124 Bug in eliminate_item_equal
+# leads to crash in Item_func::Item_func
+CREATE TABLE t1 ( f1 int(11), f3 varchar(1)) ;
+INSERT INTO t1 VALUES (5,'m'),(NULL,'c');
+CREATE TABLE t2 ( f2 int(11), f3 varchar(1)) ;
+INSERT INTO t2 VALUES (6,'f'),(2,'d');
+CREATE TABLE t3 ( f2 int(11), f3 varchar(1)) ;
+INSERT INTO t3 VALUES (6,'f'),(2,'d');
+SELECT * FROM t3
+WHERE ( f2 ) IN (SELECT t1.f1
+FROM t1 STRAIGHT_JOIN t2 ON t2.f3 = t1.f3
+WHERE t2.f3 = 'c');
+f2	f3
+drop table t1,t2,t3;
+#
+# LP BUG#718593 Crash in substitute_for_best_equal_field ->
+# eliminate_item_equal -> Item_field::find_item_equal -> Item_equal::contains
diff --git a/mysql-test/r/subselect_no_mat.result b/mysql-test/r/subselect_no_mat.result
index 7ab96bad552..c693f21798c 100644
--- a/mysql-test/r/subselect_no_mat.result
+++ b/mysql-test/r/subselect_no_mat.result
@@ -1,6 +1,6 @@
 select @@optimizer_switch like '%materialization=on%';
 @@optimizer_switch like '%materialization=on%'
-1
+0
 set optimizer_switch='materialization=off';
 drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t11,t12;
 drop view if exists v2;
@@ -427,7 +427,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where 1
+Note	1003	select 1 AS `1` from `test`.`t1` where (1 = (select 1 union select 1))
 drop table t1;
 CREATE TABLE `t1` (
 `numeropost` mediumint(8) unsigned NOT NULL auto_increment,
@@ -913,7 +913,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref_or_null	a	a	5	func	2	100.00	Using where; Using index
 2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
+Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`a` from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
 drop table t1,t2,t3;
 create table t1 (a float);
 select 10.5 IN (SELECT * from t1 LIMIT 1);
@@ -1184,9 +1184,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)
@@ -1194,9 +1194,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 drop table t1;
 CREATE TABLE `t1` (
 `i` int(11) NOT NULL default '0',
@@ -1539,34 +1539,34 @@ select * from t3 where NULL >= any (select b from t2);
 a
 explain extended select * from t3 where NULL >= any (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(NULL) from `test`.`t2`)))
 select * from t3 where NULL >= any (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= any (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select NULL from `test`.`t2` group by 1)))
 select * from t3 where NULL >= some (select b from t2);
 a
 explain extended select * from t3 where NULL >= some (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(NULL) from `test`.`t2`)))
 select * from t3 where NULL >= some (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= some (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select NULL from `test`.`t2` group by 1)))
 insert into t2 values (2,2), (2,1), (3,3), (3,1);
 select * from t3 where a > all (select max(b) from t2 group by a);
 a
@@ -1575,7 +1575,7 @@ a
 explain extended select * from t3 where a > all (select max(b) from t2 group by a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary
 Warnings:
 Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <not>((`test`.`t3`.`a` <= <max>(select max(`test`.`t2`.`b`) from `test`.`t2` group by `test`.`t2`.`a`)))
 drop table t2, t3;
@@ -1628,7 +1628,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 'e' AS `s1` from `test`.`t1` where 1
+Note	1003	select 'e' AS `s1` from `test`.`t1` where <nop>(('f' > <min>(select 'e' from `test`.`t1` union select 'e' from `test`.`t1`)))
 drop table t1;
 CREATE TABLE t1 (number char(11) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1;
 INSERT INTO t1 VALUES ('69294728265'),('18621828126'),('89356874041'),('95895001874');
@@ -2841,7 +2841,7 @@ Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `tes
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cache><`test`.`t1`.`two`,`test`.`t1`.`one`>(<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one`,`test`.`t2`.`two` from `test`.`t2` where (`test`.`t2`.`flag` = '0') group by `test`.`t2`.`one`,`test`.`t2`.`two` having (trigcond(((<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) or isnull(`test`.`t2`.`one`))) and trigcond(((<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`) or isnull(`test`.`t2`.`two`))) and trigcond(<is_not_null_test>(`test`.`t2`.`one`)) and trigcond(<is_not_null_test>(`test`.`t2`.`two`)))))) AS `test` from `test`.`t1`
 DROP TABLE t1,t2;
@@ -3113,10 +3113,10 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
-4
 1
+2
 3
+4
 SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
 (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b));
@@ -3125,8 +3125,8 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
 1
+2
 3
 4
 SELECT a FROM t1
@@ -3423,7 +3423,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 ALTER TABLE t1 ADD INDEX(a);
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 a	b
@@ -3434,7 +3434,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	Using filesort
+2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	
 DROP TABLE t1;
 create table t1( f1 int,f2 int);
 insert into t1 values (1,1),(2,2);
@@ -4324,15 +4324,15 @@ INSERT INTO t1 VALUES (1),(2);
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having 1)))
+Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having (<cache>(1) = <ref_null_helper>(1)))))
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 WHERE a > 3 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary; Using filesort
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having 1))
+Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having (<cache>(1) = <ref_null_helper>(1)))))
 DROP TABLE t1;
 #
 # Bug#45061: Incorrectly market field caused wrong result.
@@ -5073,4 +5073,4 @@ DROP table t1,t2;
 set optimizer_switch=default;
 select @@optimizer_switch like '%materialization=on%';
 @@optimizer_switch like '%materialization=on%'
-1
+0
diff --git a/mysql-test/r/subselect_no_opts.result b/mysql-test/r/subselect_no_opts.result
index 6f923c0e626..07b5d5d72ac 100644
--- a/mysql-test/r/subselect_no_opts.result
+++ b/mysql-test/r/subselect_no_opts.result
@@ -424,7 +424,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where 1
+Note	1003	select 1 AS `1` from `test`.`t1` where (1 = (select 1 union select 1))
 drop table t1;
 CREATE TABLE `t1` (
 `numeropost` mediumint(8) unsigned NOT NULL auto_increment,
@@ -910,7 +910,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref_or_null	a	a	5	func	2	100.00	Using where; Using index
 2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
+Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`a` from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
 drop table t1,t2,t3;
 create table t1 (a float);
 select 10.5 IN (SELECT * from t1 LIMIT 1);
@@ -1181,9 +1181,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)
@@ -1191,9 +1191,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 drop table t1;
 CREATE TABLE `t1` (
 `i` int(11) NOT NULL default '0',
@@ -1321,7 +1321,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t1	eq_ref	PRIMARY	PRIMARY	4	func	1	100.00	Using where
 2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.b	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select 1 from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
 drop table t1, t2, t3;
 create table t1 (a int, b int, index a (a,b));
 create table t2 (a int, index a (a));
@@ -1364,7 +1364,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t1	ref	a	a	5	func	1001	100.00	Using index
 2	DEPENDENT SUBQUERY	t3	index	a	a	5	NULL	3	100.00	Using where; Using index; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select 1 from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
 insert into t1 values (3,31);
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
@@ -1536,34 +1536,34 @@ select * from t3 where NULL >= any (select b from t2);
 a
 explain extended select * from t3 where NULL >= any (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(NULL) from `test`.`t2`)))
 select * from t3 where NULL >= any (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= any (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select NULL from `test`.`t2` group by 1)))
 select * from t3 where NULL >= some (select b from t2);
 a
 explain extended select * from t3 where NULL >= some (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(NULL) from `test`.`t2`)))
 select * from t3 where NULL >= some (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= some (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select NULL from `test`.`t2` group by 1)))
 insert into t2 values (2,2), (2,1), (3,3), (3,1);
 select * from t3 where a > all (select max(b) from t2 group by a);
 a
@@ -1572,7 +1572,7 @@ a
 explain extended select * from t3 where a > all (select max(b) from t2 group by a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary
 Warnings:
 Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <not>((`test`.`t3`.`a` <= <max>(select max(`test`.`t2`.`b`) from `test`.`t2` group by `test`.`t2`.`a`)))
 drop table t2, t3;
@@ -1625,7 +1625,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 'e' AS `s1` from `test`.`t1` where 1
+Note	1003	select 'e' AS `s1` from `test`.`t1` where <nop>(('f' > <min>(select 'e' from `test`.`t1` union select 'e' from `test`.`t1`)))
 drop table t1;
 CREATE TABLE t1 (number char(11) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1;
 INSERT INTO t1 VALUES ('69294728265'),('18621828126'),('89356874041'),('95895001874');
@@ -2838,7 +2838,7 @@ Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `tes
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cache><`test`.`t1`.`two`,`test`.`t1`.`one`>(<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one`,`test`.`t2`.`two` from `test`.`t2` where (`test`.`t2`.`flag` = '0') group by `test`.`t2`.`one`,`test`.`t2`.`two` having (trigcond(((<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) or isnull(`test`.`t2`.`one`))) and trigcond(((<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`) or isnull(`test`.`t2`.`two`))) and trigcond(<is_not_null_test>(`test`.`t2`.`one`)) and trigcond(<is_not_null_test>(`test`.`t2`.`two`)))))) AS `test` from `test`.`t1`
 DROP TABLE t1,t2;
@@ -3110,10 +3110,10 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
-4
 1
+2
 3
+4
 SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
 (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b));
@@ -3122,8 +3122,8 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
 1
+2
 3
 4
 SELECT a FROM t1
@@ -3420,7 +3420,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 ALTER TABLE t1 ADD INDEX(a);
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 a	b
@@ -3431,7 +3431,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	Using filesort
+2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	
 DROP TABLE t1;
 create table t1( f1 int,f2 int);
 insert into t1 values (1,1),(2,2);
@@ -4321,15 +4321,15 @@ INSERT INTO t1 VALUES (1),(2);
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having 1)))
+Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having (<cache>(1) = <ref_null_helper>(1)))))
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 WHERE a > 3 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary; Using filesort
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having 1))
+Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having (<cache>(1) = <ref_null_helper>(1)))))
 DROP TABLE t1;
 #
 # Bug#45061: Incorrectly market field caused wrong result.
diff --git a/mysql-test/r/subselect_no_semijoin.result b/mysql-test/r/subselect_no_semijoin.result
index 889735b1dc2..63b12e4df5f 100644
--- a/mysql-test/r/subselect_no_semijoin.result
+++ b/mysql-test/r/subselect_no_semijoin.result
@@ -424,7 +424,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where 1
+Note	1003	select 1 AS `1` from `test`.`t1` where (1 = (select 1 union select 1))
 drop table t1;
 CREATE TABLE `t1` (
 `numeropost` mediumint(8) unsigned NOT NULL auto_increment,
@@ -910,7 +910,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref_or_null	a	a	5	func	2	100.00	Using where; Using index
 2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
+Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`a` from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
 drop table t1,t2,t3;
 create table t1 (a float);
 select 10.5 IN (SELECT * from t1 LIMIT 1);
@@ -1181,9 +1181,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)
@@ -1191,9 +1191,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 drop table t1;
 CREATE TABLE `t1` (
 `i` int(11) NOT NULL default '0',
@@ -1298,9 +1298,9 @@ a
 explain extended select * from t2 where t2.a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	100.00	Using where; Using index
-2	SUBQUERY	t1	index	NULL	PRIMARY	4	NULL	4	100.00	Using index
+2	DEPENDENT SUBQUERY	t1	unique_subquery	PRIMARY	PRIMARY	4	func	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,`test`.`t2`.`a` in ( <materialize> (select `test`.`t1`.`a` from `test`.`t1` ), <primary_index_lookup>(`test`.`t2`.`a` in <temporary table> on distinct_key where ((`test`.`t2`.`a` = `materialized subselect`.`a`))))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(<primary_index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on PRIMARY))))
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
 2
@@ -1308,9 +1308,9 @@ a
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	100.00	Using where; Using index
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
+2	DEPENDENT SUBQUERY	t1	unique_subquery	PRIMARY	PRIMARY	4	func	1	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,`test`.`t2`.`a` in ( <materialize> (select `test`.`t1`.`a` from `test`.`t1` where (`test`.`t1`.`b` <> 30) ), <primary_index_lookup>(`test`.`t2`.`a` in <temporary table> on distinct_key where ((`test`.`t2`.`a` = `materialized subselect`.`a`))))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(<primary_index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on PRIMARY where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))))))
 select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 a
 2
@@ -1318,10 +1318,10 @@ a
 explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	100.00	Using where; Using index
-2	SUBQUERY	t3	index	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where; Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	t1	eq_ref	PRIMARY	PRIMARY	4	func	1	100.00	Using where
+2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.b	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,`test`.`t2`.`a` in ( <materialize> (select `test`.`t1`.`a` from `test`.`t1` join `test`.`t3` where (`test`.`t1`.`b` = `test`.`t3`.`a`) ), <primary_index_lookup>(`test`.`t2`.`a` in <temporary table> on distinct_key where ((`test`.`t2`.`a` = `materialized subselect`.`a`))))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
 drop table t1, t2, t3;
 create table t1 (a int, b int, index a (a,b));
 create table t2 (a int, index a (a));
@@ -1341,9 +1341,9 @@ a
 explain extended select * from t2 where t2.a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	SUBQUERY	t1	index	NULL	a	10	NULL	10004	100.00	Using index
+2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1001	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,`test`.`t2`.`a` in ( <materialize> (select `test`.`t1`.`a` from `test`.`t1` ), <primary_index_lookup>(`test`.`t2`.`a` in <temporary table> on distinct_key where ((`test`.`t2`.`a` = `materialized subselect`.`a`))))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a))))
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
 2
@@ -1351,9 +1351,9 @@ a
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	SUBQUERY	t1	index	NULL	a	10	NULL	10004	100.00	Using where; Using index
+2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1001	100.00	Using index; Using where
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,`test`.`t2`.`a` in ( <materialize> (select `test`.`t1`.`a` from `test`.`t1` where (`test`.`t1`.`b` <> 30) ), <primary_index_lookup>(`test`.`t2`.`a` in <temporary table> on distinct_key where ((`test`.`t2`.`a` = `materialized subselect`.`a`))))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))))))
 select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 a
 2
@@ -1361,10 +1361,10 @@ a
 explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	SUBQUERY	t3	index	a	a	5	NULL	3	100.00	Using index
-2	SUBQUERY	t1	index	NULL	a	10	NULL	10004	100.00	Using where; Using index; Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	t1	ref	a	a	5	func	1001	100.00	Using index
+2	DEPENDENT SUBQUERY	t3	index	a	a	5	NULL	3	100.00	Using where; Using index; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,`test`.`t2`.`a` in ( <materialize> (select `test`.`t1`.`a` from `test`.`t1` join `test`.`t3` where (`test`.`t1`.`b` = `test`.`t3`.`a`) ), <primary_index_lookup>(`test`.`t2`.`a` in <temporary table> on distinct_key where ((`test`.`t2`.`a` = `materialized subselect`.`a`))))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(select `test`.`t1`.`a` from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
 insert into t1 values (3,31);
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
@@ -1378,9 +1378,9 @@ a
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	SUBQUERY	t1	index	NULL	a	10	NULL	10005	100.00	Using where; Using index
+2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1001	100.00	Using index; Using where
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,`test`.`t2`.`a` in ( <materialize> (select `test`.`t1`.`a` from `test`.`t1` where (`test`.`t1`.`b` <> 30) ), <primary_index_lookup>(`test`.`t2`.`a` in <temporary table> on distinct_key where ((`test`.`t2`.`a` = `materialized subselect`.`a`))))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <expr_cache><`test`.`t2`.`a`>(<in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))))))
 drop table t0, t1, t2, t3;
 create table t1 (a int, b int);
 create table t2 (a int, b int);
@@ -1536,34 +1536,34 @@ select * from t3 where NULL >= any (select b from t2);
 a
 explain extended select * from t3 where NULL >= any (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(NULL) from `test`.`t2`)))
 select * from t3 where NULL >= any (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= any (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select NULL from `test`.`t2` group by 1)))
 select * from t3 where NULL >= some (select b from t2);
 a
 explain extended select * from t3 where NULL >= some (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(NULL) from `test`.`t2`)))
 select * from t3 where NULL >= some (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= some (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select NULL from `test`.`t2` group by 1)))
 insert into t2 values (2,2), (2,1), (3,3), (3,1);
 select * from t3 where a > all (select max(b) from t2 group by a);
 a
@@ -1572,7 +1572,7 @@ a
 explain extended select * from t3 where a > all (select max(b) from t2 group by a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary
 Warnings:
 Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <not>((`test`.`t3`.`a` <= <max>(select max(`test`.`t2`.`b`) from `test`.`t2` group by `test`.`t2`.`a`)))
 drop table t2, t3;
@@ -1625,7 +1625,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 'e' AS `s1` from `test`.`t1` where 1
+Note	1003	select 'e' AS `s1` from `test`.`t1` where <nop>(('f' > <min>(select 'e' from `test`.`t1` union select 'e' from `test`.`t1`)))
 drop table t1;
 CREATE TABLE t1 (number char(11) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1;
 INSERT INTO t1 VALUES ('69294728265'),('18621828126'),('89356874041'),('95895001874');
@@ -2832,13 +2832,13 @@ Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cac
 explain extended SELECT one,two from t1 where ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = 'N');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` where <expr_cache><`test`.`t1`.`two`,`test`.`t1`.`one`>(<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),(`test`.`t1`.`one`,`test`.`t1`.`two`) in ( <materialize> (select `test`.`t2`.`one`,`test`.`t2`.`two` from `test`.`t2` where (`test`.`t2`.`flag` = 'N') ), <primary_index_lookup>(`test`.`t1`.`one` in <temporary table> on distinct_key where ((`test`.`t1`.`one` = `materialized subselect`.`one`) and (`test`.`t1`.`two` = `materialized subselect`.`two`))))))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` where <expr_cache><`test`.`t1`.`two`,`test`.`t1`.`one`>(<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one`,`test`.`t2`.`two` from `test`.`t2` where ((`test`.`t2`.`flag` = 'N') and (<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) and (<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`)))))
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cache><`test`.`t1`.`two`,`test`.`t1`.`one`>(<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one`,`test`.`t2`.`two` from `test`.`t2` where (`test`.`t2`.`flag` = '0') group by `test`.`t2`.`one`,`test`.`t2`.`two` having (trigcond(((<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) or isnull(`test`.`t2`.`one`))) and trigcond(((<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`) or isnull(`test`.`t2`.`two`))) and trigcond(<is_not_null_test>(`test`.`t2`.`one`)) and trigcond(<is_not_null_test>(`test`.`t2`.`two`)))))) AS `test` from `test`.`t1`
 DROP TABLE t1,t2;
@@ -3110,10 +3110,10 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
-4
 1
+2
 3
+4
 SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
 (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b));
@@ -3122,8 +3122,8 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
 1
+2
 3
 4
 SELECT a FROM t1
@@ -3420,7 +3420,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 ALTER TABLE t1 ADD INDEX(a);
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 a	b
@@ -3431,7 +3431,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	
 DROP TABLE t1;
 create table t1( f1 int,f2 int);
 insert into t1 values (1,1),(2,2);
@@ -4201,7 +4201,7 @@ CREATE INDEX I2 ON t1 (b);
 EXPLAIN SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	SUBQUERY	t1	index	NULL	I1	2	NULL	2	Using index
+2	DEPENDENT SUBQUERY	t1	index_subquery	I1	I1	2	func	2	Using index; Using where
 SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1);
 a	b
 CREATE TABLE t2 (a VARCHAR(1), b VARCHAR(10));
@@ -4211,14 +4211,14 @@ CREATE INDEX I2 ON t2 (b);
 EXPLAIN SELECT a,b FROM t2 WHERE b IN (SELECT a FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	SUBQUERY	t2	index	NULL	I1	4	NULL	2	Using index
+2	DEPENDENT SUBQUERY	t2	index_subquery	I1	I1	4	func	2	Using index; Using where
 SELECT a,b FROM t2 WHERE b IN (SELECT a FROM t2);
 a	b
 EXPLAIN
 SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1 WHERE LENGTH(a)<500);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	SUBQUERY	t1	index	NULL	I1	2	NULL	2	Using where; Using index
+2	DEPENDENT SUBQUERY	t1	index_subquery	I1	I1	2	func	2	Using index; Using where
 SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1 WHERE LENGTH(a)<500);
 a	b
 DROP TABLE t1,t2;
@@ -4320,16 +4320,16 @@ CREATE TABLE t1 (a INT);
 INSERT INTO t1 VALUES (1),(2);
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,1 in ( <materialize> (select 1 from `test`.`t1` group by `test`.`t1`.`a` ), <primary_index_lookup>(1 in <temporary table> on distinct_key where ((1 = `materialized subselect`.`1`))))))
+Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having (<cache>(1) = <ref_null_helper>(1)))))
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 WHERE a > 3 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary; Using filesort
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,1 in ( <materialize> (select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` ), <primary_index_lookup>(1 in <temporary table> on distinct_key where ((1 = `materialized subselect`.`1`))))))
+Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having (<cache>(1) = <ref_null_helper>(1)))))
 DROP TABLE t1;
 #
 # Bug#45061: Incorrectly market field caused wrong result.
@@ -5014,8 +5014,8 @@ FROM it2,it3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	
 1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
-2	SUBQUERY	it2	ALL	NULL	NULL	NULL	NULL	4	
-2	SUBQUERY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	it2	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	DEPENDENT SUBQUERY	it3	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer (flat, BNL join)
 DROP TABLE IF EXISTS ot1, ot4, it2, it3;
 #
 # Bug#729039: NULL keys used to evaluate subquery
@@ -5059,8 +5059,8 @@ INSERT INTO t2 VALUES (15,4);
 EXPLAIN SELECT * FROM t1 WHERE pk IN (SELECT it.pk FROM t2 JOIN t2 AS it ON 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
-2	SUBQUERY	t2	index	NULL	PRIMARY	4	NULL	3	Using index
-2	SUBQUERY	it	index	NULL	PRIMARY	4	NULL	3	Using index; Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	t2	index	NULL	PRIMARY	4	NULL	3	Using index
+2	DEPENDENT SUBQUERY	it	eq_ref	PRIMARY	PRIMARY	4	func	1	Using index
 SELECT * FROM t1 WHERE pk IN (SELECT it.pk FROM t2 JOIN t2 AS it ON 1);
 pk	i
 11	0
diff --git a/mysql-test/r/subselect_sj.result b/mysql-test/r/subselect_sj.result
index 1fc5955f493..30a42b0c8e7 100644
--- a/mysql-test/r/subselect_sj.result
+++ b/mysql-test/r/subselect_sj.result
@@ -406,24 +406,6 @@ SELECT t1 .varchar_key  from t1
 int_key
 9
 7
-SELECT t0.int_key  
-FROM t0
-WHERE t0.varchar_nokey  IN (  
-SELECT t1_1 .varchar_key  
-FROM t1 AS t1_1  JOIN t1 AS t1_2 ON t1_1 .int_key
-);
-int_key
-9
-7
-SELECT t0.int_key  
-FROM t0, t2
-WHERE t0.varchar_nokey  IN (  
-SELECT t1_1 .varchar_key  
-FROM t1 AS t1_1  JOIN t1 AS t1_2 ON t1_1 .int_key  
-);
-int_key
-9
-7
 DROP TABLE t0, t1, t2;
 # End of bug#46550
 #
@@ -774,11 +756,11 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select 1 from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
 show warnings;
 Level	Code	Message
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select 1 from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
 select a from t1
 where a in (select c from t2 where d >= some(select e from t3 where b=e));
 a
@@ -811,10 +793,9 @@ INSERT INTO t2 VALUES (1,'i','iiii','iiii','iiii','iiii','ffff','ffff','ffff','f
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	13	func	1	1.00	
-2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Rowid-ordered scan
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
-Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`pk` > 0))
+Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 pk
 2
@@ -980,10 +961,9 @@ FROM t1
 WHERE `varchar_nokey`  < 'n' XOR `pk`  )   ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	18	100.00	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	8	func	1	1.00	
-2	SUBQUERY	t1	ALL	varchar_key	NULL	NULL	NULL	15	100.00	Using where
+1	PRIMARY	t1	ref	varchar_key	varchar_key	3	test.t2.varchar_nokey	2	105.00	Using where; FirstMatch(t2)
 Warnings:
-Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_nokey` = `test`.`t1`.`varchar_key`) and ((`test`.`t1`.`varchar_key` < 'n') xor `test`.`t1`.`pk`))
+Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_key` = `test`.`t2`.`varchar_nokey`) and (`test`.`t1`.`varchar_nokey` = `test`.`t2`.`varchar_nokey`) and ((`test`.`t2`.`varchar_nokey` < 'n') xor `test`.`t1`.`pk`))
 SELECT varchar_nokey
 FROM t2  
 WHERE ( `varchar_nokey`  , `varchar_nokey`  )  IN (  
@@ -1061,11 +1041,9 @@ WHERE  t2.val LIKE 'a%' OR t2.val LIKE 'e%')
 AND t1.val IN (SELECT t3.val FROM t3
 WHERE  t3.val LIKE 'a%' OR t3.val LIKE 'e%');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	
-1	PRIMARY	subselect3	eq_ref	unique_key	unique_key	14	func	1	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	14	func	1	
-3	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	Start temporary
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	5	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; End temporary; Using join buffer (flat, BNL join)
 SELECT *
 FROM t1
 WHERE t1.val IN (SELECT t2.val FROM t2
diff --git a/mysql-test/r/subselect_sj2.result b/mysql-test/r/subselect_sj2.result
index 56c0f45ea1d..064ec3f6dfc 100644
--- a/mysql-test/r/subselect_sj2.result
+++ b/mysql-test/r/subselect_sj2.result
@@ -32,9 +32,8 @@ a	b
 9	5
 explain select * from t2 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	3	
-1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
+1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	End temporary
 select * from t2 where b in (select a from t1);
 a	b
 1	1
@@ -51,9 +50,8 @@ primary key(pk1, pk2, pk3)
 insert into t3 select a,a, a,a,a from t0;
 explain select * from t3 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	b	NULL	NULL	NULL	10	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
+1	PRIMARY	t3	ref	b	b	5	test.t1.a	1	End temporary
 select * from t3 where b in (select a from t1);
 a	b	pk1	pk2	pk3
 1	1	1	1	1
@@ -75,9 +73,8 @@ A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a
 from t0 A, t0 B where B.a <5;
 explain select * from t3 where b in (select a from t0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	
-2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	End temporary
 set @save_ecp= @@engine_condition_pushdown;
 set engine_condition_pushdown=0;
 select * from t3 where b in (select A.a+B.a from t0 A, t0 B where B.a<5);
@@ -101,9 +98,8 @@ set join_buffer_size= @save_join_buffer_size;
 set max_heap_table_size= @save_max_heap_table_size;
 explain select * from t1 where a in (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t2	index	b	b	5	NULL	10	Using index
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	Using index; FirstMatch(t1)
 select * from t1;
 a	b
 1	1
@@ -130,9 +126,8 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	22	
-1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	32	Using where; Using join buffer (flat, BNL join)
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
+1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	22	Start temporary
+1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	32	Using where; End temporary; Using join buffer (flat, BNL join)
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -164,8 +159,7 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	32	
+1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	32	Using where; FirstMatch(ot)
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
 from t2 ot where a in (select a from t1 it);
@@ -198,9 +192,8 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	22	
-1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	52	Using where; Using join buffer (flat, BNL join)
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
+1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	22	Start temporary
+1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	52	Using where; End temporary; Using join buffer (flat, BNL join)
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -232,8 +225,7 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	52	
+1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	52	Using where; FirstMatch(ot)
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
 from t2 ot where a in (select a from t1 it);
@@ -349,8 +341,7 @@ WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	31	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	3	func	1	
-2	SUBQUERY	t2	ALL	CountryCode	NULL	NULL	NULL	545	Using where
+1	PRIMARY	t2	ref	CountryCode	CountryCode	3	test.t1.Code	18	Using where; FirstMatch(t1)
 SELECT Name FROM t1 
 WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
@@ -692,9 +683,8 @@ alter table t3 add primary key(id), add key(a);
 The following must use loose index scan over t3, key a:
 explain select count(a) from t2 where a in ( SELECT  a FROM t3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	index	a	a	5	NULL	1000	Using index
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t3	index	a	a	5	NULL	30000	Using index
+1	PRIMARY	t2	index	a	a	5	NULL	1000	Using where; Using index
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	30	Using index; FirstMatch(t2)
 select count(a) from t2 where a in ( SELECT  a FROM t3);
 count(a)
 1000
diff --git a/mysql-test/r/subselect_sj2_jcl6.result b/mysql-test/r/subselect_sj2_jcl6.result
index 31da487158e..7b3b31b66fc 100644
--- a/mysql-test/r/subselect_sj2_jcl6.result
+++ b/mysql-test/r/subselect_sj2_jcl6.result
@@ -39,9 +39,8 @@ a	b
 9	5
 explain select * from t2 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	3	
-1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
+1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 select * from t2 where b in (select a from t1);
 a	b
 1	1
@@ -58,9 +57,8 @@ primary key(pk1, pk2, pk3)
 insert into t3 select a,a, a,a,a from t0;
 explain select * from t3 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	b	NULL	NULL	NULL	10	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
+1	PRIMARY	t3	ref	b	b	5	test.t1.a	1	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 select * from t3 where b in (select a from t1);
 a	b	pk1	pk2	pk3
 1	1	1	1	1
@@ -82,9 +80,8 @@ A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a
 from t0 A, t0 B where B.a <5;
 explain select * from t3 where b in (select a from t0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
-2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
+1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 set @save_ecp= @@engine_condition_pushdown;
 set engine_condition_pushdown=0;
 select * from t3 where b in (select A.a+B.a from t0 A, t0 B where B.a<5);
@@ -108,9 +105,8 @@ set join_buffer_size= @save_join_buffer_size;
 set max_heap_table_size= @save_max_heap_table_size;
 explain select * from t1 where a in (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t2	index	b	b	5	NULL	10	Using index
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	Using index; FirstMatch(t1)
 select * from t1;
 a	b
 1	1
@@ -137,9 +133,8 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	22	
-1	PRIMARY	ot	hash_ALL	NULL	#hash#$hj	5	test.it.a	32	Using where; Using join buffer (flat, BNLH join)
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	Using where
+1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	22	Using where; Start temporary
+1	PRIMARY	ot	hash_ALL	NULL	#hash#$hj	5	test.it.a	32	Using where; End temporary; Using join buffer (flat, BNLH join)
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -171,8 +166,7 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	32	
+1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	32	Using where; FirstMatch(ot); Using join buffer (flat, BNL join)
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
 from t2 ot where a in (select a from t1 it);
@@ -196,8 +190,8 @@ a	mid(filler1, 1,10)	length(filler1)=length(filler2)
 16	filler1234	1
 17	filler1234	1
 18	filler1234	1
-19	filler1234	1
 3	duplicate 	1
+19	filler1234	1
 19	duplicate 	1
 insert into t1 select a+20, 'filler123456', 'filler123456' from t0;
 insert into t1 select a+20, 'filler123456', 'filler123456' from t0;
@@ -205,9 +199,8 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	22	
-1	PRIMARY	ot	hash_ALL	NULL	#hash#$hj	5	test.it.a	52	Using where; Using join buffer (flat, BNLH join)
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	Using where
+1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	22	Using where; Start temporary
+1	PRIMARY	ot	hash_ALL	NULL	#hash#$hj	5	test.it.a	52	Using where; End temporary; Using join buffer (flat, BNLH join)
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -239,8 +232,7 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	52	
+1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	52	Using where; FirstMatch(ot); Using join buffer (flat, BNL join)
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
 from t2 ot where a in (select a from t1 it);
@@ -264,8 +256,8 @@ a	mid(filler1, 1,10)	length(filler1)=length(filler2)
 16	filler1234	1
 17	filler1234	1
 18	filler1234	1
-19	filler1234	1
 3	duplicate 	1
+19	filler1234	1
 19	duplicate 	1
 drop table t1, t2;
 create table t1 (a int, b int, key(a));
@@ -356,8 +348,7 @@ WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	31	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	3	func	1	
-2	SUBQUERY	t2	ALL	CountryCode	NULL	NULL	NULL	545	Using where
+1	PRIMARY	t2	ref	CountryCode	CountryCode	3	test.t1.Code	18	Using where; FirstMatch(t1); Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 SELECT Name FROM t1 
 WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
@@ -701,9 +692,8 @@ alter table t3 add primary key(id), add key(a);
 The following must use loose index scan over t3, key a:
 explain select count(a) from t2 where a in ( SELECT  a FROM t3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	index	a	a	5	NULL	1000	Using index
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t3	index	a	a	5	NULL	30000	Using index
+1	PRIMARY	t2	index	a	a	5	NULL	1000	Using where; Using index
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	30	Using index; FirstMatch(t2)
 select count(a) from t2 where a in ( SELECT  a FROM t3);
 count(a)
 1000
diff --git a/mysql-test/r/subselect_sj2_mat.result b/mysql-test/r/subselect_sj2_mat.result
new file mode 100644
index 00000000000..c54f1e9fd6b
--- /dev/null
+++ b/mysql-test/r/subselect_sj2_mat.result
@@ -0,0 +1,731 @@
+set optimizer_switch='materialization=on';
+drop table if exists t0, t1, t2, t3;
+drop view if exists v1;
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1 (
+a int, 
+b int
+);
+insert into t1 values (1,1),(1,1),(2,2);
+create table t2 (
+a int,
+b int,
+key(b)
+);
+insert into t2 select a, a/2 from t0;
+select * from t1;
+a	b
+1	1
+1	1
+2	2
+select * from t2;
+a	b
+0	0
+1	1
+2	1
+3	2
+4	2
+5	3
+6	3
+7	4
+8	4
+9	5
+explain select * from t2 where b in (select a from t1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	3	
+1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+select * from t2 where b in (select a from t1);
+a	b
+1	1
+2	1
+3	2
+4	2
+create table t3 (
+a int, 
+b int,
+key(b),
+pk1 char(200), pk2 char(200), pk3 char(200),
+primary key(pk1, pk2, pk3)
+) engine=innodb;
+insert into t3 select a,a, a,a,a from t0;
+explain select * from t3 where b in (select a from t1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t3	ALL	b	NULL	NULL	NULL	10	
+1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
+select * from t3 where b in (select a from t1);
+a	b	pk1	pk2	pk3
+1	1	1	1	1
+2	2	2	2	2
+set @save_max_heap_table_size= @@max_heap_table_size;
+set max_heap_table_size=16384;
+set @save_join_buffer_size = @@join_buffer_size;
+set join_buffer_size= 8000;
+drop table t3;
+create table t3 (
+a int, 
+b int,
+key(b),
+pk1 char(200), pk2 char(200),
+primary key(pk1, pk2)
+) engine=innodb;
+insert into t3 select 
+A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a 
+from t0 A, t0 B where B.a <5;
+explain select * from t3 where b in (select a from t0);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	
+2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where
+set @save_ecp= @@engine_condition_pushdown;
+set engine_condition_pushdown=0;
+select * from t3 where b in (select A.a+B.a from t0 A, t0 B where B.a<5);
+a	b	pk1	pk2
+0	0	0	0
+1	1	1	1
+2	2	2	2
+3	3	3	3
+4	4	4	4
+5	5	5	5
+6	6	6	6
+7	7	7	7
+8	8	8	8
+9	9	9	9
+10	10	10	10
+11	11	11	11
+12	12	12	12
+13	13	13	13
+set engine_condition_pushdown=@save_ecp;
+set join_buffer_size= @save_join_buffer_size;
+set max_heap_table_size= @save_max_heap_table_size;
+explain select * from t1 where a in (select b from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
+1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
+2	SUBQUERY	t2	index	b	b	5	NULL	10	Using index
+select * from t1;
+a	b
+1	1
+1	1
+2	2
+select * from t1 where a in (select b from t2);
+a	b
+1	1
+1	1
+2	2
+drop table t1, t2, t3;
+set @save_join_buffer_size = @@join_buffer_size;
+set join_buffer_size= 8000;
+create table t1 (a int, filler1 binary(200), filler2 binary(200));
+insert into t1 select a, 'filler123456', 'filler123456' from t0;
+insert into t1 select a+10, 'filler123456', 'filler123456' from t0;
+create table t2 as select * from t1;
+insert into t1 select a+20, 'filler123456', 'filler123456' from t0;
+insert into t1 values (2, 'duplicate ok', 'duplicate ok');
+insert into t1 values (18, 'duplicate ok', 'duplicate ok');
+insert into t2 values (3, 'duplicate ok', 'duplicate ok');
+insert into t2 values (19, 'duplicate ok', 'duplicate ok');
+explain select 
+a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
+from t1 ot where a in (select a from t2 it);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	22	
+1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	32	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
+select 
+a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
+from t1 ot where a in (select a from t2 it);
+a	mid(filler1, 1,10)	Z
+0	filler1234	1
+1	filler1234	1
+2	filler1234	1
+3	filler1234	1
+4	filler1234	1
+5	filler1234	1
+6	filler1234	1
+7	filler1234	1
+8	filler1234	1
+9	filler1234	1
+10	filler1234	1
+11	filler1234	1
+12	filler1234	1
+13	filler1234	1
+14	filler1234	1
+15	filler1234	1
+16	filler1234	1
+17	filler1234	1
+18	filler1234	1
+19	filler1234	1
+2	duplicate 	1
+18	duplicate 	1
+explain select 
+a, mid(filler1, 1,10), length(filler1)=length(filler2) 
+from t2 ot where a in (select a from t1 it);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
+1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	32	
+select 
+a, mid(filler1, 1,10), length(filler1)=length(filler2) 
+from t2 ot where a in (select a from t1 it);
+a	mid(filler1, 1,10)	length(filler1)=length(filler2)
+0	filler1234	1
+1	filler1234	1
+2	filler1234	1
+3	filler1234	1
+4	filler1234	1
+5	filler1234	1
+6	filler1234	1
+7	filler1234	1
+8	filler1234	1
+9	filler1234	1
+10	filler1234	1
+11	filler1234	1
+12	filler1234	1
+13	filler1234	1
+14	filler1234	1
+15	filler1234	1
+16	filler1234	1
+17	filler1234	1
+18	filler1234	1
+19	filler1234	1
+3	duplicate 	1
+19	duplicate 	1
+insert into t1 select a+20, 'filler123456', 'filler123456' from t0;
+insert into t1 select a+20, 'filler123456', 'filler123456' from t0;
+explain select 
+a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
+from t1 ot where a in (select a from t2 it);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	22	
+1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	52	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
+select 
+a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
+from t1 ot where a in (select a from t2 it);
+a	mid(filler1, 1,10)	Z
+0	filler1234	1
+1	filler1234	1
+2	filler1234	1
+3	filler1234	1
+4	filler1234	1
+5	filler1234	1
+6	filler1234	1
+7	filler1234	1
+8	filler1234	1
+9	filler1234	1
+10	filler1234	1
+11	filler1234	1
+12	filler1234	1
+13	filler1234	1
+14	filler1234	1
+15	filler1234	1
+16	filler1234	1
+17	filler1234	1
+18	filler1234	1
+19	filler1234	1
+2	duplicate 	1
+18	duplicate 	1
+explain select 
+a, mid(filler1, 1,10), length(filler1)=length(filler2) 
+from t2 ot where a in (select a from t1 it);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
+1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	52	
+select 
+a, mid(filler1, 1,10), length(filler1)=length(filler2) 
+from t2 ot where a in (select a from t1 it);
+a	mid(filler1, 1,10)	length(filler1)=length(filler2)
+0	filler1234	1
+1	filler1234	1
+2	filler1234	1
+3	filler1234	1
+4	filler1234	1
+5	filler1234	1
+6	filler1234	1
+7	filler1234	1
+8	filler1234	1
+9	filler1234	1
+10	filler1234	1
+11	filler1234	1
+12	filler1234	1
+13	filler1234	1
+14	filler1234	1
+15	filler1234	1
+16	filler1234	1
+17	filler1234	1
+18	filler1234	1
+19	filler1234	1
+3	duplicate 	1
+19	duplicate 	1
+drop table t1, t2;
+create table t1 (a int, b int, key(a));
+create table t2 (a int, b int, key(a));
+create table t3 (a int, b int, key(a));
+insert into t1 select a,a from t0;
+insert into t2 select a,a from t0;
+insert into t3 select a,a from t0;
+t2 and t3 must be use 'ref', not 'ALL':
+explain select * 
+from t0 where a in
+(select t2.a+t3.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	Start temporary
+1	PRIMARY	t1	index	NULL	a	5	NULL	10	Using index; Using join buffer (flat, BNL join)
+1	PRIMARY	t2	ref	a	a	5	test.t1.a	1	Using where; Using index
+1	PRIMARY	t3	ref	a	a	5	test.t1.a	1	Using where; Using index; End temporary
+drop table t0, t1,t2,t3;
+CREATE TABLE t1 (
+ID int(11) NOT NULL auto_increment,
+Name char(35) NOT NULL default '',
+Country char(3) NOT NULL default '',
+Population int(11) NOT NULL default '0',
+PRIMARY KEY  (ID),
+INDEX (Population),
+INDEX (Country) 
+);
+CREATE TABLE t2 (
+Code char(3) NOT NULL default '',
+Name char(52) NOT NULL default '',
+SurfaceArea float(10,2) NOT NULL default '0.00',
+Population int(11) NOT NULL default '0',
+Capital int(11) default NULL,
+PRIMARY KEY  (Code),
+UNIQUE INDEX (Name),
+INDEX (Population)
+);
+CREATE TABLE t3 (
+Country char(3) NOT NULL default '',
+Language char(30) NOT NULL default '',
+Percentage float(3,1) NOT NULL default '0.0',
+PRIMARY KEY  (Country, Language),
+INDEX (Percentage)
+);
+EXPLAIN
+SELECT Name FROM t2 
+WHERE t2.Code IN (SELECT Country FROM t1 WHERE Population > 5000000)
+AND
+t2.Code IN (SELECT Country FROM t3 
+WHERE Language='English' AND Percentage > 10 AND
+t2.Population > 100000);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	range	Population,Country	Population	4	NULL	1	Using index condition; Rowid-ordered scan
+1	PRIMARY	t3	eq_ref	PRIMARY,Percentage	PRIMARY	33	test.t1.Country,const	1	Using index condition; Using where
+1	PRIMARY	t2	eq_ref	PRIMARY,Population	PRIMARY	3	test.t1.Country	1	Using where
+DROP TABLE t1,t2,t3;
+CREATE TABLE t1 (
+Code char(3) NOT NULL DEFAULT '',
+Name char(52) NOT NULL DEFAULT '',
+Continent enum('Asia','Europe','North America','Africa','Oceania','Antarctica','South America') NOT NULL DEFAULT 'Asia',
+Region char(26) NOT NULL DEFAULT '',
+SurfaceArea float(10,2) NOT NULL DEFAULT '0.00',
+IndepYear smallint(6) DEFAULT NULL,
+Population int(11) NOT NULL DEFAULT '0',
+LifeExpectancy float(3,1) DEFAULT NULL,
+GNP float(10,2) DEFAULT NULL,
+GNPOld float(10,2) DEFAULT NULL,
+LocalName char(45) NOT NULL DEFAULT '',
+GovernmentForm char(45) NOT NULL DEFAULT '',
+HeadOfState char(60) DEFAULT NULL,
+Capital int(11) DEFAULT NULL,
+Code2 char(2) NOT NULL DEFAULT '',
+PRIMARY KEY (Code)
+);
+CREATE TABLE t2 (
+ID int(11) NOT NULL AUTO_INCREMENT,
+Name char(35) NOT NULL DEFAULT '',
+CountryCode char(3) NOT NULL DEFAULT '',
+District char(20) NOT NULL DEFAULT '',
+Population int(11) NOT NULL DEFAULT '0',
+PRIMARY KEY (ID),
+KEY CountryCode (CountryCode)
+);
+Fill the table with test data
+This must not use LooseScan:
+EXPLAIN SELECT Name FROM t1 
+WHERE t1.Code IN (
+SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	31	
+1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	3	func	1	
+2	SUBQUERY	t2	ALL	CountryCode	NULL	NULL	NULL	545	Using where
+SELECT Name FROM t1 
+WHERE t1.Code IN (
+SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
+Name
+Austria
+Canada
+China
+Czech Republic
+drop table t1, t2;
+CREATE TABLE t1(a INT);
+CREATE TABLE t2(c INT);
+CREATE PROCEDURE p1(v1 int)
+BEGIN
+SELECT 1 FROM t1 WHERE a = v1 AND a IN (SELECT c FROM t2);
+END
+//
+CREATE PROCEDURE p2(v1 int)
+BEGIN
+SELECT 1 FROM t1 WHERE a IN (SELECT c FROM t2);
+END
+//
+CREATE PROCEDURE p3(v1 int)
+BEGIN
+SELECT 1 
+FROM 
+t1 t01,t1 t02,t1 t03,t1 t04,t1 t05,t1 t06,t1 t07,t1 t08,
+t1 t09,t1 t10,t1 t11,t1 t12,t1 t13,t1 t14,t1 t15,t1 t16,
+t1 t17,t1 t18,t1 t19,t1 t20,t1 t21,t1 t22,t1 t23,t1 t24,
+t1 t25,t1 t26,t1 t27,t1 t28,t1 t29,t1 t30,t1 t31,t1 t32,
+t1 t33,t1 t34,t1 t35,t1 t36,t1 t37,t1 t38,t1 t39,t1 t40,
+t1 t41,t1 t42,t1 t43,t1 t44,t1 t45,t1 t46,t1 t47,t1 t48,
+t1 t49,t1 t50,t1 t51,t1 t52,t1 t53,t1 t54,t1 t55,t1 t56,
+t1 t57,t1 t58,t1 t59,t1 t60
+WHERE t01.a IN (SELECT c FROM t2);
+END
+//
+CREATE PROCEDURE p4(v1 int)
+BEGIN
+SELECT 1 
+FROM 
+t1 t01,t1 t02,t1 t03,t1 t04,t1 t05,t1 t06,t1 t07,t1 t08,
+t1 t09,t1 t10,t1 t11,t1 t12,t1 t13,t1 t14,t1 t15,t1 t16,
+t1 t17,t1 t18,t1 t19,t1 t20,t1 t21,t1 t22,t1 t23,t1 t24,
+t1 t25,t1 t26,t1 t27,t1 t28,t1 t29,t1 t30,t1 t31,t1 t32,
+t1 t33,t1 t34,t1 t35,t1 t36,t1 t37,t1 t38,t1 t39,t1 t40,
+t1 t41,t1 t42,t1 t43,t1 t44,t1 t45,t1 t46,t1 t47,t1 t48,
+t1 t49,t1 t50,t1 t51,t1 t52,t1 t53,t1 t54,t1 t55,t1 t56,
+t1 t57,t1 t58,t1 t59,t1 t60
+WHERE t01.a = v1 AND t01.a IN (SELECT c FROM t2);
+END
+//
+CALL p1(1);
+1
+CALL p2(1);
+1
+CALL p3(1);
+1
+CALL p4(1);
+1
+DROP TABLE t1, t2;
+DROP PROCEDURE p1;
+DROP PROCEDURE p2;
+DROP PROCEDURE p3;
+DROP PROCEDURE p4;
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4);
+create table t1 (a int, b int, key(a));
+insert into t1 select a,a from t0;
+create table t2 (a int, b int, primary key(a));
+insert into t2 select * from t1;
+Table t2, unlike table t1, should be displayed as pulled out
+explain extended select * from t0
+where t0.a in ( select t1.a from t1,t2 where t2.a=t0.a and
+t1.b=t2.b);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Start temporary
+1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	Using where; End temporary
+Warnings:
+Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
+Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = `test`.`t0`.`a`) and (`test`.`t2`.`a` = `test`.`t0`.`a`))
+update t1 set a=3, b=11 where a=4;
+update t2 set b=11 where a=3;
+select * from t0 where t0.a in 
+(select t1.a from t1, t2 where t2.a=t0.a and t1.b=t2.b);
+a
+0
+1
+2
+3
+drop table t0, t1, t2;
+CREATE TABLE t1 (
+id int(11) NOT NULL,
+PRIMARY KEY (id));
+CREATE TABLE t2 (
+id int(11) NOT NULL,
+fid int(11) NOT NULL,
+PRIMARY KEY (id));
+insert into t1 values(1);
+insert into t2 values(1,7503),(2,1);
+explain select count(*) 
+from t1 
+where fid IN (select fid from t2 where (id between 7502 and 8420) order by fid );
+ERROR 42S22: Unknown column 'fid' in 'IN/ALL/ANY subquery'
+drop table t1, t2;
+create table t1 (a int, b int, key (a), key (b));
+insert into t1 values (2,4),(2,4),(2,4);
+select t1.a from t1 
+where 
+t1.a in (select 1 from t1 where t1.a in (select 1 from t1) group by  t1.a);
+a
+drop table t1;
+create table t1(a int,b int,key(a),key(b));
+insert into t1 values (1,1),(2,2),(3,3);
+select 1 from t1 
+where t1.a not in (select 1 from t1 
+where t1.a in (select 1 from t1) 
+group by  t1.b);
+1
+1
+1
+drop table t1;
+CREATE TABLE t1
+(EMPNUM   CHAR(3) NOT NULL,
+EMPNAME  CHAR(20),
+GRADE    DECIMAL(4),
+CITY     CHAR(15));
+CREATE TABLE t2
+(PNUM     CHAR(3) NOT NULL,
+PNAME    CHAR(20),
+PTYPE    CHAR(6),
+BUDGET   DECIMAL(9),
+CITY     CHAR(15));
+CREATE TABLE t3
+(EMPNUM   CHAR(3) NOT NULL,
+PNUM     CHAR(3) NOT NULL,
+HOURS    DECIMAL(5));
+INSERT INTO t1 VALUES ('E1','Alice',12,'Deale');
+INSERT INTO t1 VALUES ('E2','Betty',10,'Vienna');
+INSERT INTO t1 VALUES ('E3','Carmen',13,'Vienna');
+INSERT INTO t1 VALUES ('E4','Don',12,'Deale');
+INSERT INTO t1 VALUES ('E5','Ed',13,'Akron');
+INSERT INTO t2 VALUES ('P1','MXSS','Design',10000,'Deale');
+INSERT INTO t2 VALUES ('P2','CALM','Code',30000,'Vienna');
+INSERT INTO t2 VALUES ('P3','SDP','Test',30000,'Tampa');
+INSERT INTO t2 VALUES ('P4','SDP','Design',20000,'Deale');
+INSERT INTO t2 VALUES ('P5','IRM','Test',10000,'Vienna');
+INSERT INTO t2 VALUES ('P6','PAYR','Design',50000,'Deale');
+INSERT INTO t3 VALUES  ('E1','P1',40);
+INSERT INTO t3 VALUES  ('E1','P2',20);
+INSERT INTO t3 VALUES  ('E1','P3',80);
+INSERT INTO t3 VALUES  ('E1','P4',20);
+INSERT INTO t3 VALUES  ('E1','P5',12);
+INSERT INTO t3 VALUES  ('E1','P6',12);
+INSERT INTO t3 VALUES  ('E2','P1',40);
+INSERT INTO t3 VALUES  ('E2','P2',80);
+INSERT INTO t3 VALUES  ('E3','P2',20);
+INSERT INTO t3 VALUES  ('E4','P2',20);
+INSERT INTO t3 VALUES  ('E4','P4',40);
+INSERT INTO t3 VALUES  ('E4','P5',80);
+SELECT * FROM t1;
+EMPNUM	EMPNAME	GRADE	CITY
+E1	Alice	12	Deale
+E2	Betty	10	Vienna
+E3	Carmen	13	Vienna
+E4	Don	12	Deale
+E5	Ed	13	Akron
+CREATE UNIQUE INDEX t1_IDX ON t1(EMPNUM);
+SELECT EMPNAME
+FROM t1
+WHERE EMPNUM IN
+(SELECT EMPNUM
+FROM t3
+WHERE PNUM IN
+(SELECT PNUM
+FROM t2
+WHERE PTYPE = 'Design'));
+EMPNAME
+Alice
+Betty
+Don
+DROP INDEX t1_IDX ON t1;
+CREATE INDEX t1_IDX ON t1(EMPNUM);
+SELECT EMPNAME
+FROM t1
+WHERE EMPNUM IN
+(SELECT EMPNUM
+FROM t3
+WHERE PNUM IN
+(SELECT PNUM
+FROM t2
+WHERE PTYPE = 'Design'));
+EMPNAME
+Alice
+Betty
+Don
+DROP INDEX t1_IDX ON t1;
+SELECT EMPNAME
+FROM t1
+WHERE EMPNUM IN
+(SELECT EMPNUM
+FROM t3
+WHERE PNUM IN
+(SELECT PNUM
+FROM t2
+WHERE PTYPE = 'Design'));
+EMPNAME
+Alice
+Betty
+Don
+DROP TABLE t1, t2, t3;
+CREATE TABLE t1 (f1 INT NOT NULL);
+CREATE VIEW v1 (a) AS SELECT f1 IN (SELECT f1 FROM t1) FROM t1;
+SELECT * FROM v1;
+a
+drop view v1;
+drop table t1;
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1(a int, b int);
+insert into t1 values (0,0),(1,1),(2,2);
+create table t2 as select * from t1;
+create table t3 (pk int, a int, primary key(pk));
+insert into t3 select a,a from t0;
+explain 
+select * from t1 left join t2 on (t2.a= t1.a and t2.a in (select pk from t3));
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	DEPENDENT SUBQUERY	t3	unique_subquery	PRIMARY	PRIMARY	4	func	1	Using index
+drop table t0, t1, t2, t3;
+create table t1 (a int);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t2 (a char(200), b char(200), c char(200), primary key (a,b,c)) engine=innodb;
+insert into t2 select concat(a, repeat('X',198)),repeat('B',200),repeat('B',200) from t1;
+insert into t2 select concat(a, repeat('Y',198)),repeat('B',200),repeat('B',200) from t1;
+alter table t2 add filler1 int;
+insert into t1 select A.a + 10*(B.a + 10*C.a) from t1 A, t1 B, t1 C;
+set @save_join_buffer_size=@@join_buffer_size;
+set join_buffer_size=1;
+select * from t2 where filler1 in ( select a from t1);
+a	b	c	filler1
+set join_buffer_size=default;
+drop table t1, t2;
+create table t1 (a int not null);
+drop procedure if exists p1;
+CREATE PROCEDURE p1()
+BEGIN
+DECLARE EXIT HANDLER FOR SQLEXCEPTION select a from t1;
+prepare s1 from '
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( 
+  select a from t1 where a in ( select a from t1) 
+  )))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))';
+execute s1;
+END;
+|
+call p1();
+a
+drop procedure p1;
+drop table t1;
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1 (a int) as select A.a + 10 *(B.a + 10*C.a) as a  from t0 A, t0 B, t0 C;
+create table t2 (id int, a int, primary key(id), key(a)) as select a as id, a as a  from t1;
+show create table t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `id` int(11) NOT NULL DEFAULT '0',
+  `a` int(11) DEFAULT NULL,
+  PRIMARY KEY (`id`),
+  KEY `a` (`a`)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+set @a=0;
+create table t3 as select * from t2 limit 0;
+insert into t3 select @a:=@a+1, t2.a from t2, t0;
+insert into t3 select @a:=@a+1, t2.a from t2, t0;
+insert into t3 select @a:=@a+1, t2.a from t2, t0;
+alter table t3 add primary key(id), add key(a);
+The following must use loose index scan over t3, key a:
+explain select count(a) from t2 where a in ( SELECT  a FROM t3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	index	a	a	5	NULL	1000	Using index
+1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
+2	SUBQUERY	t3	index	a	a	5	NULL	30000	Using index
+select count(a) from t2 where a in ( SELECT  a FROM t3);
+count(a)
+1000
+drop table t0,t1,t2,t3;
+
+BUG#42740: crash in optimize_semijoin_nests
+
+create table t1 (c6 timestamp,key (c6)) engine=innodb;
+create table t2 (c2 double) engine=innodb;
+explain select 1 from t2 where c2 = any (select log10(null) from t1 where c6 <null)  ;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+drop table t1, t2;
+# 
+# BUG#42742: crash in setup_sj_materialization, Copy_field::set
+# 
+create table t3 ( c1 year) engine=innodb;
+insert into t3 values (2135),(2142);
+create table t2 (c1 tinytext,c2 text,c6 timestamp) engine=innodb;
+# The following must not crash, EXPLAIN should show one SJ strategy, not a mix:
+explain select 1 from t2 where 
+c2 in (select 1 from t3, t2) and
+c1 in (select convert(c6,char(1)) from t2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	Using where
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	FirstMatch(t2)
+drop table t2, t3;
+set optimizer_switch=default;
+select @@optimizer_switch like '%materialization=on%';
+@@optimizer_switch like '%materialization=on%'
+0
diff --git a/mysql-test/r/subselect_sj_jcl6.result b/mysql-test/r/subselect_sj_jcl6.result
index 46ca02cd71a..0b3e9c6984e 100644
--- a/mysql-test/r/subselect_sj_jcl6.result
+++ b/mysql-test/r/subselect_sj_jcl6.result
@@ -414,24 +414,6 @@ SELECT t1 .varchar_key  from t1
 int_key
 9
 7
-SELECT t0.int_key  
-FROM t0
-WHERE t0.varchar_nokey  IN (  
-SELECT t1_1 .varchar_key  
-FROM t1 AS t1_1  JOIN t1 AS t1_2 ON t1_1 .int_key
-);
-int_key
-9
-7
-SELECT t0.int_key  
-FROM t0, t2
-WHERE t0.varchar_nokey  IN (  
-SELECT t1_1 .varchar_key  
-FROM t1 AS t1_1  JOIN t1 AS t1_2 ON t1_1 .int_key  
-);
-int_key
-9
-7
 DROP TABLE t0, t1, t2;
 # End of bug#46550
 #
@@ -782,11 +764,11 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select 1 from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
 show warnings;
 Level	Code	Message
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select 1 from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
 select a from t1
 where a in (select c from t2 where d >= some(select e from t3 where b=e));
 a
@@ -819,10 +801,9 @@ INSERT INTO t2 VALUES (1,'i','iiii','iiii','iiii','iiii','ffff','ffff','ffff','f
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	13	func	1	1.00	
-2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Rowid-ordered scan
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`pk` > 0))
+Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 pk
 2
@@ -988,10 +969,9 @@ FROM t1
 WHERE `varchar_nokey`  < 'n' XOR `pk`  )   ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	18	100.00	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	8	func	1	1.00	
-2	SUBQUERY	t1	ALL	varchar_key	NULL	NULL	NULL	15	100.00	Using where
+1	PRIMARY	t1	ref	varchar_key	varchar_key	3	test.t2.varchar_nokey	2	105.00	Using where; FirstMatch(t2); Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
-Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_nokey` = `test`.`t1`.`varchar_key`) and ((`test`.`t1`.`varchar_key` < 'n') xor `test`.`t1`.`pk`))
+Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_key` = `test`.`t2`.`varchar_nokey`) and (`test`.`t1`.`varchar_nokey` = `test`.`t2`.`varchar_nokey`) and ((`test`.`t2`.`varchar_nokey` < 'n') xor `test`.`t1`.`pk`))
 SELECT varchar_nokey
 FROM t2  
 WHERE ( `varchar_nokey`  , `varchar_nokey`  )  IN (  
@@ -1069,11 +1049,9 @@ WHERE  t2.val LIKE 'a%' OR t2.val LIKE 'e%')
 AND t1.val IN (SELECT t3.val FROM t3
 WHERE  t3.val LIKE 'a%' OR t3.val LIKE 'e%');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	
-1	PRIMARY	subselect3	eq_ref	unique_key	unique_key	14	func	1	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	14	func	1	
-3	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	Start temporary
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	5	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; End temporary; Using join buffer (incremental, BNL join)
 SELECT *
 FROM t1
 WHERE t1.val IN (SELECT t2.val FROM t2
diff --git a/mysql-test/r/union.result b/mysql-test/r/union.result
index cd3091b072b..b1832dadab4 100644
--- a/mysql-test/r/union.result
+++ b/mysql-test/r/union.result
@@ -1632,11 +1632,11 @@ ORDER BY (SELECT a FROM t2 WHERE b = 12);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
 2	UNION	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
+NULL	UNION	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	Using filesort
 3	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	Using filesort
 Warnings:
-Note	1276	Field or reference 'test.t1.a' of SELECT #3 was resolved in SELECT #2
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` union select `test`.`t1`.`a` AS `a` from `test`.`t1` order by (select `test`.`t1`.`a` from `test`.`t2` where (`test`.`t2`.`b` = 12))
+Note	1276	Field or reference 'a' of SELECT #3 was resolved in SELECT #-1
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` union select `test`.`t1`.`a` AS `a` from `test`.`t1` order by (select `a` from `test`.`t2` where (`test`.`t2`.`b` = 12))
 # Should not crash
 SELECT * FROM t1 UNION SELECT * FROM t1
 ORDER BY (SELECT a FROM t2 WHERE b = 12);
diff --git a/mysql-test/suite/pbxt/r/group_min_max.result b/mysql-test/suite/pbxt/r/group_min_max.result
index e4ba16ce527..04f14a9f5e7 100644
--- a/mysql-test/suite/pbxt/r/group_min_max.result
+++ b/mysql-test/suite/pbxt/r/group_min_max.result
@@ -1364,7 +1364,7 @@ explain select a1,a2,b,min(c),max(c) from t1
 where exists ( select * from t2 where t2.c > 'b1' )
 group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	range	NULL	idx_t1_1	147	NULL	129	Using index for group-by
+1	PRIMARY	t1	range	NULL	idx_t1_1	147	NULL	129	Using where; Using index for group-by
 2	SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
 explain select a1,a2,b,min(c),max(c) from t1 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -2247,17 +2247,17 @@ EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE EXISTS
 (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using index
-2	SUBQUERY	t1	index	NULL	a	10	NULL	15	Using index
+2	SUBQUERY	t1	index	NULL	a	10	NULL	1	Using index
 EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
 (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using index
 2	SUBQUERY	t1	index	NULL	a	10	NULL	15	Using index
 EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
 a IN (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using where; Using index
-2	SUBQUERY	t1	index	NULL	a	10	NULL	15	Using index
+2	DEPENDENT SUBQUERY	t1	index	NULL	a	10	NULL	1	Using index
 EXPLAIN SELECT 1 FROM t1 AS t1_outer GROUP BY a HAVING 
 a > (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
diff --git a/mysql-test/suite/pbxt/r/join_nested.result b/mysql-test/suite/pbxt/r/join_nested.result
index d6c4b9a7322..b4edf18f2f5 100644
--- a/mysql-test/suite/pbxt/r/join_nested.result
+++ b/mysql-test/suite/pbxt/r/join_nested.result
@@ -854,7 +854,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	ref	idx_b	idx_b	5	test.t3.b	1	100.00	Using where
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b` from `test`.`t3` join `test`.`t4` left join (`test`.`t1` join `test`.`t2`) on((((`test`.`t3`.`a` = 1) and ((`test`.`t4`.`b` = `test`.`t3`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`b`))) and (`test`.`t3`.`b` is not null))) where 1
+Note	1003	select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b` from `test`.`t3` join `test`.`t4` left join (`test`.`t1` join `test`.`t2`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t3`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`b`) and (`test`.`t3`.`b` is not null))) where 1
 SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
 FROM (t3,t4)
 LEFT JOIN              
@@ -966,7 +966,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t8	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 1	SIMPLE	t9	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on((((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`)) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t3`.`b` = `test`.`t4`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
+Note	1003	select `test`.`t0`.`a` AS `a`,`test`.`t0`.`b` AS `b`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`a` AS `a`,`test`.`t4`.`b` AS `b`,`test`.`t5`.`a` AS `a`,`test`.`t5`.`b` AS `b`,`test`.`t6`.`a` AS `a`,`test`.`t6`.`b` AS `b`,`test`.`t7`.`a` AS `a`,`test`.`t7`.`b` AS `b`,`test`.`t8`.`a` AS `a`,`test`.`t8`.`b` AS `b`,`test`.`t9`.`a` AS `a`,`test`.`t9`.`b` AS `b` from `test`.`t0` join `test`.`t1` left join (`test`.`t2` left join (`test`.`t3` join `test`.`t4`) on(((`test`.`t3`.`a` = 1) and (`test`.`t4`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`b` is not null))) join `test`.`t5` left join (`test`.`t6` join `test`.`t7` left join `test`.`t8` on(((`test`.`t6`.`b` < 10) and ((`test`.`t7`.`b` = `test`.`t5`.`b`) and (`test`.`t8`.`b` = `test`.`t5`.`b`))))) on(((`test`.`t6`.`b` >= 2) and (`test`.`t7`.`b` = `test`.`t5`.`b`)))) on((((`test`.`t3`.`b` = 2) or isnull(`test`.`t3`.`c`)) and ((`test`.`t6`.`b` = 2) or isnull(`test`.`t6`.`c`)) and (((`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t5`.`b` = `test`.`t0`.`b`)) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t6`.`c`) or isnull(`test`.`t8`.`c`)) and (`test`.`t1`.`a` <> 2))) join `test`.`t9` where ((`test`.`t9`.`a` = 1) and (`test`.`t1`.`b` = `test`.`t0`.`b`) and (`test`.`t0`.`a` = 1) and ((`test`.`t2`.`a` >= 4) or isnull(`test`.`t2`.`c`)) and ((`test`.`t3`.`a` < 5) or isnull(`test`.`t3`.`c`)) and ((`test`.`t3`.`b` = `test`.`t4`.`b`) or isnull(`test`.`t3`.`c`) or isnull(`test`.`t4`.`c`)) and ((`test`.`t5`.`a` >= 2) or isnull(`test`.`t5`.`c`)) and ((`test`.`t6`.`a` >= 4) or isnull(`test`.`t6`.`c`)) and ((`test`.`t7`.`a` <= 2) or isnull(`test`.`t7`.`c`)) and ((`test`.`t8`.`a` < 1) or isnull(`test`.`t8`.`c`)) and ((`test`.`t9`.`b` = `test`.`t8`.`b`) or isnull(`test`.`t8`.`c`)))
 CREATE INDEX idx_b ON t8(b);
 EXPLAIN
 SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
diff --git a/mysql-test/suite/pbxt/r/ps_11bugs.result b/mysql-test/suite/pbxt/r/ps_11bugs.result
index fad35b97b24..dd09e9d14f3 100644
--- a/mysql-test/suite/pbxt/r/ps_11bugs.result
+++ b/mysql-test/suite/pbxt/r/ps_11bugs.result
@@ -120,9 +120,9 @@ create table t1 (a int primary key);
 insert into t1 values (1);
 explain select * from t1 where 3 in (select (1+1) union select 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING
-3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING
+1	PRIMARY	t1	index	NULL	PRIMARY	4	NULL	1	Using index
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
 select * from t1 where 3 in (select (1+1) union select 1);
 a
diff --git a/mysql-test/suite/pbxt/r/subselect.result b/mysql-test/suite/pbxt/r/subselect.result
index 42b3a097b8a..455411c6faf 100644
--- a/mysql-test/suite/pbxt/r/subselect.result
+++ b/mysql-test/suite/pbxt/r/subselect.result
@@ -420,7 +420,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where 1
+Note	1003	select 1 AS `1` from `test`.`t1` where (1 = (select 1 union select 1))
 drop table t1;
 CREATE TABLE `t1` (
 `numeropost` mediumint(8) unsigned NOT NULL auto_increment,
@@ -908,7 +908,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ref_or_null	a	a	5	func	2	100.00	Using where; Using index
 2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
+Note	1003	select `test`.`t1`.`a` AS `a`,<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t2`.`a` from `test`.`t2` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t2`.`a`) and ((<cache>(`test`.`t1`.`a`) = `test`.`t2`.`a`) or isnull(`test`.`t2`.`a`))) having <is_not_null_test>(`test`.`t2`.`a`)))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from `test`.`t1`
 drop table t1,t2,t3;
 create table t1 (a float);
 select 10.5 IN (SELECT * from t1 LIMIT 1);
@@ -1179,9 +1179,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
 SELECT 0 IN (SELECT 1 FROM t1 a);
 0 IN (SELECT 1 FROM t1 a)
@@ -1189,9 +1189,9 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
-Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`
+Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (<cache>(0) = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 drop table t1;
 CREATE TABLE `t1` (
 `i` int(11) NOT NULL default '0',
@@ -1515,7 +1515,7 @@ a
 explain extended select * from t3 where a >= all (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	Using temporary
 Warnings:
 Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <not>((`test`.`t3`.`a` < <max>(select `test`.`t2`.`b` from `test`.`t2` group by 1)))
 select * from t3 where a >= some (select b from t2 group by 1);
@@ -1523,41 +1523,41 @@ a
 explain extended select * from t3 where a >= some (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	Using temporary
 Warnings:
 Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((`test`.`t3`.`a` >= <min>(select `test`.`t2`.`b` from `test`.`t2` group by 1)))
 select * from t3 where NULL >= any (select b from t2);
 a
 explain extended select * from t3 where NULL >= any (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(`test`.`t2`.`b`) from `test`.`t2`)))
 select * from t3 where NULL >= any (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= any (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	Using temporary; Using filesort
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	Using temporary
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select `test`.`t2`.`b` from `test`.`t2` group by 1)))
 select * from t3 where NULL >= some (select b from t2);
 a
 explain extended select * from t3 where NULL >= some (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= (select min(`test`.`t2`.`b`) from `test`.`t2`)))
 select * from t3 where NULL >= some (select b from t2 group by 1);
 a
 explain extended select * from t3 where NULL >= some (select b from t2 group by 1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	Using temporary; Using filesort
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	0	0.00	Using temporary
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <nop>((NULL >= <min>(select `test`.`t2`.`b` from `test`.`t2` group by 1)))
 insert into t2 values (2,2), (2,1), (3,3), (3,1);
 select * from t3 where a > all (select max(b) from t2 group by a);
 a
@@ -1566,7 +1566,7 @@ a
 explain extended select * from t3 where a > all (select max(b) from t2 group by a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary; Using filesort
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	100.00	Using temporary
 Warnings:
 Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <not>((`test`.`t3`.`a` <= <max>(select max(`test`.`t2`.`b`) from `test`.`t2` group by `test`.`t2`.`a`)))
 drop table t2, t3;
@@ -1619,7 +1619,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	UNION	t1	ALL	NULL	NULL	NULL	NULL	1	100.00	
 NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
-Note	1003	select `test`.`t1`.`s1` AS `s1` from `test`.`t1` where 1
+Note	1003	select `test`.`t1`.`s1` AS `s1` from `test`.`t1` where <nop>(('f' > <min>(select `test`.`t1`.`s1` from `test`.`t1` union select `test`.`t1`.`s1` from `test`.`t1`)))
 drop table t1;
 CREATE TABLE t1 (number char(11) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1;
 INSERT INTO t1 VALUES ('69294728265'),('18621828126'),('89356874041'),('95895001874');
@@ -2829,14 +2829,13 @@ Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cac
 explain extended SELECT one,two from t1 where ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = 'N');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	10	func	1	1.00	
-2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; FirstMatch(t1)
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`flag` = 'N'))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`two` = `test`.`t1`.`two`) and (`test`.`t2`.`one` = `test`.`t1`.`one`) and (`test`.`t2`.`flag` = 'N'))
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cache><`test`.`t1`.`two`,`test`.`t1`.`one`>(<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one`,`test`.`t2`.`two` from `test`.`t2` where (`test`.`t2`.`flag` = '0') group by `test`.`t2`.`one`,`test`.`t2`.`two` having (trigcond(((<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) or isnull(`test`.`t2`.`one`))) and trigcond(((<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`) or isnull(`test`.`t2`.`two`))) and trigcond(<is_not_null_test>(`test`.`t2`.`one`)) and trigcond(<is_not_null_test>(`test`.`t2`.`two`)))))) AS `test` from `test`.`t1`
 DROP TABLE t1,t2;
@@ -3112,10 +3111,10 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
-4
 1
+2
 3
+4
 SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
 (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b));
@@ -3124,8 +3123,8 @@ SELECT a FROM t1
 ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
 a
-2
 1
+2
 3
 4
 SELECT a FROM t1
@@ -3422,7 +3421,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 ALTER TABLE t1 ADD INDEX(a);
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 a	b
@@ -3433,7 +3432,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	
 DROP TABLE t1;
 create table t1( f1 int,f2 int);
 insert into t1 values (1,1),(2,2);
diff --git a/mysql-test/suite/pbxt/t/subselect.test b/mysql-test/suite/pbxt/t/subselect.test
index 19658cb202e..3f4d6a9a870 100644
--- a/mysql-test/suite/pbxt/t/subselect.test
+++ b/mysql-test/suite/pbxt/t/subselect.test
@@ -2052,7 +2052,7 @@ SELECT b, MAX(c) FROM t2 GROUP BY b, (SELECT c FROM t2 WHERE b > 2);
 --error 1242
 SELECT b, MAX(c) FROM t2 GROUP BY b, (SELECT c FROM t2 WHERE b > 1);
 
-
+--sorted_result
 SELECT a FROM t1 GROUP BY a
   HAVING IFNULL((SELECT b FROM t2 WHERE b > 2),
                 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
@@ -2060,7 +2060,7 @@ SELECT a FROM t1 GROUP BY a
 SELECT a FROM t1 GROUP BY a
   HAVING IFNULL((SELECT b FROM t2 WHERE b > 1),
                 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
-
+--sorted_result
 SELECT a FROM t1 GROUP BY a
   HAVING IFNULL((SELECT b FROM t2 WHERE b > 4),
                 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
@@ -2068,7 +2068,7 @@ SELECT a FROM t1 GROUP BY a
 SELECT a FROM t1 GROUP BY a
   HAVING IFNULL((SELECT b FROM t2 WHERE b > 4),
                 (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b)) > 3;
-
+--sorted_result
 SELECT a FROM t1
   ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
                   (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
@@ -2076,7 +2076,7 @@ SELECT a FROM t1
 SELECT a FROM t1
   ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
                   (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b));
-
+--sorted_result
 SELECT a FROM t1
   ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
                   (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
diff --git a/mysql-test/t/disabled.def b/mysql-test/t/disabled.def
index 2c54131e08a..ea1de2b5a5a 100644
--- a/mysql-test/t/disabled.def
+++ b/mysql-test/t/disabled.def
@@ -19,3 +19,4 @@ main.mysqlhotcopy_myisam : Bug#56817 2010-10-21 anitha mysqlhotcopy* fails
 main.mysqlhotcopy_archive: Bug#56817 2010-10-21 anitha mysqlhotcopy* fails
 log_tables-big           : Bug#48646 2010-11-15 mattiasj report already exists
 read_many_rows_innodb    : Bug#37635 2010-11-15 mattiasj report already exists
+main.subselect_mat_cost  : MWL#89 tests that must be adjusted to the cost model introduced after the code review
diff --git a/mysql-test/t/func_group.test b/mysql-test/t/func_group.test
index 6e0a3fe2589..de06bd90f2b 100644
--- a/mysql-test/t/func_group.test
+++ b/mysql-test/t/func_group.test
@@ -1141,6 +1141,9 @@ INSERT INTO t1 VALUES (1,'c'),(2,NULL);
 INSERT INTO t2 VALUES (3,'m'),(4,NULL);
 INSERT INTO t3 VALUES (1,'n');
 
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
+
 --echo
 --echo #
 --echo # 1) Test that subquery materialization is setup for query with
@@ -1188,10 +1191,6 @@ FROM t2);
 --echo # 3) Test that subquery materialization is setup for query with
 --echo #    premature optimize() exit due to "Select tables optimized away"
 --echo #
---echo # NOTE: The result of this query is actually wrong; it should be NULL
---echo # See BUG#47762. Even so, the test case is still needed to test
---echo # that the HAVING subquery does not crash the server
---echo # 
 SELECT MIN(pk)
 FROM t1
 WHERE pk=NULL
@@ -1250,6 +1249,8 @@ HAVING ('m') IN (
 SELECT v
 FROM t2);
 
+set @@optimizer_switch=@save_optimizer_switch;
+
 --echo #
 --echo # Cleanup for BUG#46680
 --echo #
diff --git a/mysql-test/t/group_min_max.test b/mysql-test/t/group_min_max.test
index 8ab7e1c9cb4..1ba06bee942 100644
--- a/mysql-test/t/group_min_max.test
+++ b/mysql-test/t/group_min_max.test
@@ -406,11 +406,61 @@ explain select a1,a2,b,min(c),max(c) from t1
 where exists ( select * from t2 where t2.c = t1.c )
 group by a1,a2,b;
 
+select a1,a2,b,min(c),max(c) from t1
+where exists ( select * from t2 where t2.c = t1.c )
+group by a1,a2,b;
+
 # the sub-select is unrelated to MIN/MAX
 explain select a1,a2,b,min(c),max(c) from t1
 where exists ( select * from t2 where t2.c > 'b1' )
 group by a1,a2,b;
 
+select a1,a2,b,min(c),max(c) from t1
+where exists ( select * from t2 where t2.c > 'b1' )
+group by a1,a2,b;
+
+# correlated subselect that doesn't reference the min/max argument
+explain select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2 where t1.b > 'a' and t2.c > 'b1' )
+group by a1,a2,b;
+
+select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2 where t1.b > 'a' and t2.c > 'b1' )
+group by a1,a2,b;
+
+explain select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2
+               where t2.c in (select c from t3 where t3.c > t1.b) and
+               t2.c > 'b1' )
+group by a1,a2,b;
+
+select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2
+               where t2.c in (select c from t3 where t3.c > t1.b) and
+               t2.c > 'b1' )
+group by a1,a2,b;
+
+# correlated subselect that references the min/max argument
+explain select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2 where t1.c > 'a' and t2.c > 'b1' )
+group by a1,a2,b;
+
+select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2 where t1.c > 'a' and t2.c > 'b1' )
+group by a1,a2,b;
+
+explain select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2
+               where t2.c in (select c from t3 where t3.c > t1.c) and
+               t2.c > 'b1' )
+group by a1,a2,b;
+
+select a1,a2,b,c,min(c), max(c) from t1
+where exists ( select * from t2
+               where t2.c in (select c from t3 where t3.c > t1.c) and
+               t2.c > 'b1' )
+group by a1,a2,b;
+
 
 # A,B,C) Predicates referencing mixed classes of attributes
 # plans
diff --git a/mysql-test/t/subselect.test b/mysql-test/t/subselect.test
index 2015ab83513..ea5abb24561 100644
--- a/mysql-test/t/subselect.test
+++ b/mysql-test/t/subselect.test
@@ -2078,7 +2078,7 @@ SELECT b, MAX(c) FROM t2 GROUP BY b, (SELECT c FROM t2 WHERE b > 2);
 --error ER_SUBQUERY_NO_1_ROW
 SELECT b, MAX(c) FROM t2 GROUP BY b, (SELECT c FROM t2 WHERE b > 1);
 
-
+--sorted_result
 SELECT a FROM t1 GROUP BY a
   HAVING IFNULL((SELECT b FROM t2 WHERE b > 2),
                 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
@@ -2086,7 +2086,7 @@ SELECT a FROM t1 GROUP BY a
 SELECT a FROM t1 GROUP BY a
   HAVING IFNULL((SELECT b FROM t2 WHERE b > 1),
                 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
-
+--sorted_result
 SELECT a FROM t1 GROUP BY a
   HAVING IFNULL((SELECT b FROM t2 WHERE b > 4),
                 (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
@@ -2094,7 +2094,7 @@ SELECT a FROM t1 GROUP BY a
 SELECT a FROM t1 GROUP BY a
   HAVING IFNULL((SELECT b FROM t2 WHERE b > 4),
                 (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b)) > 3;
-
+--sorted_result
 SELECT a FROM t1
   ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
                   (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
@@ -2102,7 +2102,7 @@ SELECT a FROM t1
 SELECT a FROM t1
   ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
                   (SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b));
-
+--sorted_result
 SELECT a FROM t1
   ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
                   (SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
diff --git a/mysql-test/t/subselect3.test b/mysql-test/t/subselect3.test
index dc625239e84..0c1523a04ca 100644
--- a/mysql-test/t/subselect3.test
+++ b/mysql-test/t/subselect3.test
@@ -683,7 +683,8 @@ SELECT a, ROW(11, 12) = (SELECT a, 12), ROW(11, 12) IN (SELECT a, 12) FROM t1;
 # The x alias is used below to workaround bug #40674.
 # Regression tests for sum function on outer column in subselect from dual:
 SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 22), ROW(11, 12) IN (SELECT MAX(x), 22) FROM t1;
---echo # 2nd and 3rd columns should be same for x == 11 only
+--echo # 2nd and 3rd columns should be same
+EXPLAIN SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 12), ROW(11, 12) IN (SELECT MAX(x), 12) FROM t1;
 SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 12), ROW(11, 12) IN (SELECT MAX(x), 12) FROM t1;
 
 DROP TABLE t1;
diff --git a/mysql-test/t/subselect4.test b/mysql-test/t/subselect4.test
index 5cc44ca5557..4b262a070cc 100644
--- a/mysql-test/t/subselect4.test
+++ b/mysql-test/t/subselect4.test
@@ -318,7 +318,7 @@ INSERT INTO t3 VALUES  ('E4','P5',80);
 
 SET @old_optimizer_switch = @@session.optimizer_switch;
 SET @old_join_cache_level = @@session.join_cache_level;
-SET SESSION optimizer_switch = 'firstmatch=on,loosescan=on,materialization=on,semijoin=on';
+SET SESSION optimizer_switch = 'firstmatch=on,loosescan=on,materialization=on,in_to_exists=off,semijoin=on';
 SET SESSION join_cache_level = 1;
 
 CREATE UNIQUE INDEX t1_IDX ON t1(EMPNUM);
@@ -528,7 +528,7 @@ INSERT INTO t3 VALUES  ('E4','P5',80);
 
 SET @old_optimizer_switch = @@session.optimizer_switch;
 SET @old_join_cache_level = @@session.join_cache_level;
-SET SESSION optimizer_switch = 'firstmatch=on,loosescan=on,materialization=on,semijoin=on';
+SET SESSION optimizer_switch = 'firstmatch=on,loosescan=on,materialization=on,in_to_exists=off,semijoin=on';
 SET SESSION join_cache_level = 1;
 
 CREATE UNIQUE INDEX t1_IDX ON t1(EMPNUM);
@@ -661,7 +661,7 @@ CREATE TABLE t2 (f11 varchar(1)) ;
 INSERT INTO t2 VALUES ('f'),('d');
 
 SET @old_optimizer_switch = @@session.optimizer_switch;
-SET SESSION optimizer_switch = 'materialization=on';
+SET SESSION optimizer_switch = 'materialization=on,in_to_exists=off,';
 
 EXPLAIN
 SELECT * FROM t1
@@ -695,7 +695,7 @@ CREATE TABLE t2 (f3 int, f4 int not null, PRIMARY KEY (f3));
 
 set @save_optimizer_switch=@@optimizer_switch;
 
-SET @@optimizer_switch = 'materialization=on,semijoin=off';
+SET @@optimizer_switch = 'materialization=on,in_to_exists=off,semijoin=off';
 
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2);
@@ -746,7 +746,7 @@ SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2);
 
 
-SET @@optimizer_switch = 'materialization=off,semijoin=off';
+SET @@optimizer_switch = 'materialization=off,in_to_exists=on,semijoin=off';
 
 
 EXPLAIN
@@ -803,7 +803,7 @@ INSERT INTO t1 VALUES (3, 4);
 INSERT INTO t2 VALUES (5, 6);
 INSERT INTO t2 VALUES (7, 8);
 
-SET @@optimizer_switch = 'materialization=on,semijoin=off';
+SET @@optimizer_switch = 'materialization=on,in_to_exists=off,semijoin=off';
 
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2 WHERE f3 > 10);
@@ -853,7 +853,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2 WHERE f3 > 10);
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT min(f3)+f3, min(f4)+f3+max(f4) FROM t2 WHERE f3 > 10);
 
-SET @@optimizer_switch = 'materialization=off,semijoin=off';
+SET @@optimizer_switch = 'materialization=off,in_to_exists=on,semijoin=off';
 
 EXPLAIN
 SELECT * FROM t1 WHERE (2, 0) NOT IN (SELECT f3, min(f4) FROM t2 WHERE f3 > 10);
@@ -934,7 +934,7 @@ INSERT INTO t2 VALUES (1,7,'p');
 
 set @save_optimizer_switch=@@optimizer_switch;
 
-set @@optimizer_switch='materialization=off,semijoin=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
 
 EXPLAIN
 SELECT t1.f3, MAX(t1.f2)
@@ -945,7 +945,7 @@ SELECT t1.f3, MAX(t1.f2)
 FROM t1, t2
 WHERE (t2.pk = t1.pk) AND t2.pk IN (SELECT f2 FROM t1);
 
-set @@optimizer_switch='materialization=on,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 
 EXPLAIN
 SELECT t1.f3, MAX(t1.f2)
@@ -963,3 +963,410 @@ WHERE (t2.pk = t1.pk) AND t2.pk IN (SELECT f2 FROM t1);
 set @@optimizer_switch=@save_optimizer_switch;
 
 drop table t1, t2;
+
+--echo #
+--echo # LP BUG#641203 Query returns rows where no result is expected (impossible WHERE)
+--echo #
+
+CREATE TABLE t1 (c1 varchar(1) DEFAULT NULL);
+CREATE TABLE t2 (c1 varchar(1) DEFAULT NULL);
+INSERT INTO t2 VALUES ('k'), ('d');
+CREATE TABLE t3 (c1 varchar(1) DEFAULT NULL);
+INSERT INTO t3 VALUES ('a'), ('b'), ('c');
+CREATE TABLE t4 (c1 varchar(1) primary key);
+INSERT INTO t4 VALUES ('k'), ('d');
+
+EXPLAIN
+SELECT * FROM t1 RIGHT JOIN t2 ON t1.c1 WHERE 's' IN (SELECT c1 FROM t2);
+SELECT * FROM t1 RIGHT JOIN t2 ON t1.c1 WHERE 's' IN (SELECT c1 FROM t2);
+EXPLAIN
+SELECT * FROM t2 LEFT JOIN t1 ON t1.c1 WHERE 's' IN (SELECT c1 FROM t2);
+SELECT * FROM t2 LEFT JOIN t1 ON t1.c1 WHERE 's' IN (SELECT c1 FROM t2);
+EXPLAIN
+SELECT * FROM (t2 LEFT JOIN t1 ON t1.c1) LEFT JOIN t3 on t3.c1 WHERE 's' IN (SELECT c1 FROM t2);
+SELECT * FROM (t2 LEFT JOIN t1 ON t1.c1) LEFT JOIN t3 on t3.c1 WHERE 's' IN (SELECT c1 FROM t2);
+EXPLAIN
+SELECT * FROM t4 LEFT JOIN t2 ON t4.c1 WHERE 's' IN (SELECT c1 FROM t2);
+SELECT * FROM t4 LEFT JOIN t2 ON t4.c1 WHERE 's' IN (SELECT c1 FROM t2);
+drop table t1, t2, t3, t4;
+
+--echo #
+--echo # LP BUG#675981 Assertion `cache != __null' failed in sub_select_cache()
+--echo #               on EXPLAIN
+--echo #
+
+CREATE TABLE t1 (f1 int,f2 int) ;
+INSERT IGNORE INTO t1 VALUES ('2','5'),('2',NULL);
+
+CREATE TABLE t2 (f1 int, f5 int) ;
+INSERT IGNORE INTO t2 VALUES (1,0);
+
+CREATE TABLE t3 (f4 int) ;
+INSERT IGNORE INTO t3 VALUES (0),(0);
+
+set @@optimizer_switch='in_to_exists=on,materialization=off,semijoin=off';
+EXPLAIN
+SELECT * FROM t2
+WHERE f1 IN (SELECT t1.f2 FROM t1 JOIN t3 ON t3.f4);
+
+drop table t1, t2, t3;
+
+--echo #
+--echo # LP BUG#680005 Second assertion `cache != __null' failed in
+--echo #                sub_select_cache() on EXPLAIN
+--echo #
+
+CREATE TABLE t1 (f1 int,f2 int,f4 int,f6 int,KEY (f4)) ;
+INSERT IGNORE INTO t1 VALUES
+('1','5','1','0'),('2','1','1','0'),('2','2','2','0'),('0',NULL,'0','0'),
+('2','1','2','0'),('2','0','0','0'),('2','2','2','0'),('2','8','2','0'),
+('2','7','2','0'),('2','5','2','0'),('2',NULL,'1','0');
+
+CREATE TABLE t2 (f3 int) ;
+INSERT IGNORE INTO t2 VALUES ('7');
+
+CREATE TABLE t3 (f3 int) ;
+INSERT IGNORE INTO t3 VALUES ('2');
+
+EXPLAIN
+SELECT t1.f4
+FROM t2 JOIN t1 ON t1.f6
+WHERE
+( t1.f2 ) IN (SELECT SUBQUERY2_t1.f3
+              FROM t3 AS SUBQUERY2_t1
+                   JOIN
+                   (t1 AS SUBQUERY2_t2
+                      JOIN
+                    t1 AS SUBQUERY2_t3 ON SUBQUERY2_t3.f1)
+                   ON SUBQUERY2_t3.f2)
+GROUP BY t1.f4 ORDER BY t1.f1 LIMIT 10;
+
+drop table t1, t2, t3;
+
+--echo #
+--echo # LP BUG#680038 bool close_thread_table(THD*, TABLE**):
+--echo #               Assertion `table->key_read == 0' failed in EXPLAIN
+--echo #
+
+CREATE TABLE t1 (f1 int,f3 int,f4 int) ;
+INSERT IGNORE INTO t1 VALUES (NULL,1,0);
+
+CREATE TABLE t2 (f2 int,f4 int,f5 int) ;
+INSERT IGNORE INTO t2 VALUES (8,0,0),(5,0,0);
+
+CREATE TABLE t3 (f4 int,KEY (f4)) ;
+INSERT IGNORE INTO t3 VALUES (0),(0);
+
+set @@optimizer_switch='semijoin=off';
+
+EXPLAIN
+SELECT * FROM t1 WHERE
+(SELECT f2 FROM t2
+ WHERE f4 <= ALL
+       (SELECT SQ1_t1.f4
+        FROM t3 AS SQ1_t1 JOIN t3 AS SQ1_t3 ON SQ1_t3.f4
+        GROUP BY SQ1_t1.f4));
+
+drop table t1, t2, t3;
+
+--echo #
+--echo # BUG#52317: Assertion failing in Field_varstring::store() 
+--echo # 	    at field.cc:6833
+--echo #
+
+CREATE TABLE t1 (i INTEGER);
+INSERT INTO t1 VALUES (1);
+CREATE TABLE t2 (i INTEGER, KEY k(i));
+INSERT INTO t2 VALUES (1), (2);
+
+EXPLAIN  
+SELECT i FROM t1 WHERE (1) NOT IN (SELECT i FROM t2);
+
+DROP TABLE t2;
+DROP TABLE t1;
+
+--echo #
+--echo # LP BUG#680846: Crash in clear_tables() with subqueries
+--echo #
+
+CREATE TABLE t1 (f3 int) ;
+INSERT IGNORE INTO t1 VALUES (0),(0);
+
+CREATE TABLE t2 (f1 int,f3 int,f4 varchar(32)) ;
+INSERT IGNORE INTO t2 VALUES (1,0,'f');
+
+EXPLAIN
+SELECT COUNT(t2.f3),
+       (SELECT COUNT(f3) FROM t1 WHERE t2.f1) AS f9
+FROM t2 JOIN t1 ON t1.f3
+WHERE ('v') IN (SELECT f4 FROM t2)
+GROUP BY f9;
+
+SELECT COUNT(t2.f3),
+       (SELECT COUNT(f3) FROM t1 WHERE t2.f1) AS f9
+FROM t2 JOIN t1 ON t1.f3
+WHERE ('v') IN (SELECT f4 FROM t2)
+GROUP BY f9;
+
+EXPLAIN
+SELECT COUNT(t2.f3),
+       (SELECT COUNT(f3) FROM t1 WHERE t2.f1) AS f9
+FROM t2 JOIN t1 ON t1.f3
+WHERE ('v') IN (SELECT f4 FROM t2)
+ORDER BY f9;
+
+SELECT COUNT(t2.f3),
+       (SELECT COUNT(f3) FROM t1 WHERE t2.f1) AS f9
+FROM t2 JOIN t1 ON t1.f3
+WHERE ('v') IN (SELECT f4 FROM t2)
+ORDER BY f9;
+
+# these queries are like the ones above, but without the ON clause,
+# resulting in a different crash (failed assert)
+EXPLAIN
+SELECT COUNT(t2.f3),
+       (SELECT t2.f1 FROM t1 limit 1) AS f9
+FROM t2 JOIN t1
+WHERE ('v') IN (SELECT f4 FROM t2)
+GROUP BY f9;
+
+SELECT COUNT(t2.f3),
+       (SELECT t2.f1 FROM t1 limit 1) AS f9
+FROM t2 JOIN t1
+WHERE ('v') IN (SELECT f4 FROM t2)
+GROUP BY f9;
+
+EXPLAIN
+SELECT COUNT(t2.f3),
+       (SELECT t2.f1 FROM t1 limit 1) AS f9
+FROM t2 JOIN t1
+WHERE ('v') IN (SELECT f4 FROM t2)
+ORDER BY f9;
+
+SELECT COUNT(t2.f3),
+       (SELECT t2.f1 FROM t1 limit 1) AS f9
+FROM t2 JOIN t1
+WHERE ('v') IN (SELECT f4 FROM t2)
+ORDER BY f9;
+
+drop table t1,t2;
+
+--echo #
+--echo # LP BUG#682683 Crash in create_tmp_table called from
+--echo #               JOIN::init_execution
+--echo #
+
+CREATE TABLE t2 (f1 int) ;
+INSERT INTO t2 VALUES (1),(2);
+
+CREATE TABLE t1 (f1 int) ;
+
+EXPLAIN
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 GROUP BY field1;
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 GROUP BY field1;
+EXPLAIN
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 ORDER BY field1;
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 ORDER BY field1;
+
+INSERT INTO t1 VALUES (1),(2);
+
+EXPLAIN
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 GROUP BY field1;
+--error ER_SUBQUERY_NO_1_ROW
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 GROUP BY field1;
+EXPLAIN
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 ORDER BY field1;
+--error ER_SUBQUERY_NO_1_ROW
+SELECT (SELECT f1 FROM t1) AS field1 FROM t2 ORDER BY field1;
+
+drop table t1,t2;
+
+--echo #
+--echo # LP BUG#680943 Assertion `!table || (!table->read_set ||
+--echo # bitmap_is_set(table->read_set, field_index))' failed with subquery
+--echo #
+
+CREATE TABLE t1 (f1 int,f3 int) ;
+INSERT IGNORE INTO t1 VALUES ('6','0'),('4','0');
+
+CREATE TABLE t2 (f1 int,f2 int,f3 int) ;
+INSERT IGNORE INTO t2 VALUES ('6','0','0'),('2','0','0');
+
+SELECT f2
+FROM (SELECT * FROM t2) AS alias1
+WHERE (SELECT SQ2_t2.f1
+       FROM t1 JOIN t1 AS SQ2_t2 ON SQ2_t2.f3
+       WHERE SQ2_t2.f3 AND alias1.f1)
+ORDER BY f3 ;
+
+drop table t1,t2;
+
+--echo #
+--echo # LP BUG#715062: Wrong result with VIEW + UNION + subquery in maria-5.3-mwl89
+--echo #
+
+create table t1 (f1 int);
+create table t2 (f2 int);
+create table t3 (f3 int);
+insert into t1 values (2);
+insert into t2 values (2);
+insert into t3 values (7);
+
+CREATE VIEW v1 AS SELECT 2 UNION SELECT 2 ;
+CREATE VIEW v2 AS SELECT * from t1 UNION SELECT * from t2 ;
+
+set @save_optimizer_switch=@@optimizer_switch;
+SET @@optimizer_switch = 'in_to_exists=off,semijoin=off,materialization=on';
+
+EXPLAIN
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN ( SELECT * FROM v1 );
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN ( SELECT * FROM v1 );
+
+EXPLAIN
+SELECT ( 5 ) IN ( SELECT * FROM v1 );
+SELECT ( 5 ) IN ( SELECT * FROM v1 );
+
+EXPLAIN
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN (SELECT * FROM v2);
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN (SELECT * FROM v2);
+
+EXPLAIN
+SELECT 'bug' FROM t3 WHERE ( 5 ) IN (SELECT * FROM v2);
+SELECT 'bug' FROM t3 WHERE ( 5 ) IN (SELECT * FROM v2);
+
+EXPLAIN
+SELECT ( 5 ) IN ( SELECT * FROM v2 );
+SELECT ( 5 ) IN ( SELECT * FROM v2 );
+
+SET @@optimizer_switch = 'in_to_exists=on,semijoin=off,materialization=off';
+
+EXPLAIN
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN ( SELECT * FROM v1 );
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN ( SELECT * FROM v1 );
+
+EXPLAIN
+SELECT ( 5 ) IN ( SELECT * FROM v1 );
+SELECT ( 5 ) IN ( SELECT * FROM v1 );
+
+EXPLAIN
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN (SELECT * FROM v2);
+SELECT 'bug' FROM DUAL WHERE ( 5 ) IN (SELECT * FROM v2);
+
+EXPLAIN
+SELECT 'bug' FROM t3 WHERE ( 5 ) IN (SELECT * FROM v2);
+SELECT 'bug' FROM t3 WHERE ( 5 ) IN (SELECT * FROM v2);
+
+EXPLAIN
+SELECT ( 5 ) IN ( SELECT * FROM v2 );
+SELECT ( 5 ) IN ( SELECT * FROM v2 );
+
+set @@optimizer_switch=@save_optimizer_switch;
+
+drop table t1,t2,t3;
+drop view v1,v2;
+
+--echo #
+--echo # LP BUG#715069 Wrong result with GROUP BY inside subquery and materialization=off
+--echo #
+
+CREATE TABLE t0 ( f1 int(11), f2 int(11), f10 varchar(1), PRIMARY KEY (f1)) ;
+INSERT INTO t0 VALUES (8,8,'u'),(10,5,'o');
+
+CREATE TABLE t1 (f1a int, f2a int not null, f3a varchar(3) not null, PRIMARY KEY (f1a)) ;
+INSERT INTO t1 VALUES
+(8,8,'a1a'),
+(10,5,'b1b');
+
+CREATE TABLE t2 (f1b int, f2b int not null, f3b varchar(3) not null, PRIMARY KEY (f1b)) ;
+INSERT INTO t2 VALUES
+(10,5,'d1d');
+
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch = 'materialization=off';
+
+EXPLAIN
+SELECT alias2.f1 , alias2.f2
+FROM t0 AS alias1
+RIGHT JOIN t0 AS alias2 ON alias2.f10
+WHERE ( alias2.f1 , alias2.f2 ) IN ( SELECT f2 , f1 FROM t0 GROUP BY f2 , f1 );
+
+SELECT alias2.f1 , alias2.f2
+FROM t0 AS alias1
+RIGHT JOIN t0 AS alias2 ON alias2.f10
+WHERE ( alias2.f1 , alias2.f2 ) IN ( SELECT f2 , f1 FROM t0 GROUP BY f2 , f1 );
+
+EXPLAIN
+SELECT * FROM t2 WHERE (f1b, f2b) IN (SELECT f1a, f2a FROM t1 GROUP BY f1a, f2a);
+SELECT * FROM t2 WHERE (f1b, f2b) IN (SELECT f1a, f2a FROM t1 GROUP BY f1a, f2a);
+
+EXPLAIN
+SELECT * FROM t2 WHERE (f1b) IN (SELECT f1a FROM t1 GROUP BY f1a, f2a);
+SELECT * FROM t2 WHERE (f1b) IN (SELECT f1a FROM t1 GROUP BY f1a, f2a);
+
+SET @@optimizer_switch = 'materialization=on';
+
+EXPLAIN
+SELECT alias2.f1 , alias2.f2
+FROM t0 AS alias1
+RIGHT JOIN t0 AS alias2 ON alias2.f10
+WHERE ( alias2.f1 , alias2.f2 ) IN ( SELECT f2 , f1 FROM t0 GROUP BY f2 , f1 );
+
+SELECT alias2.f1 , alias2.f2
+FROM t0 AS alias1
+RIGHT JOIN t0 AS alias2 ON alias2.f10
+WHERE ( alias2.f1 , alias2.f2 ) IN ( SELECT f2 , f1 FROM t0 GROUP BY f2 , f1 );
+
+EXPLAIN
+SELECT * FROM t2 WHERE (f1b, f2b) IN (SELECT f1a, f2a FROM t1 GROUP BY f1a, f2a);
+SELECT * FROM t2 WHERE (f1b, f2b) IN (SELECT f1a, f2a FROM t1 GROUP BY f1a, f2a);
+
+EXPLAIN
+SELECT * FROM t2 WHERE (f1b) IN (SELECT f1a FROM t1 GROUP BY f1a, f2a);
+SELECT * FROM t2 WHERE (f1b) IN (SELECT f1a FROM t1 GROUP BY f1a, f2a);
+
+set @@optimizer_switch=@save_optimizer_switch;
+
+drop table t0,t1,t2;
+
+--echo #                                                                                                                                                     
+--echo # LP BUG#718593 Crash in substitute_for_best_equal_field -> eliminate_item_equal -> 
+--echo # Item_field::find_item_equal -> Item_equal::contains
+--echo #                                                                                                                                                     
+
+set @save_optimizer_switch=@@optimizer_switch;
+SET @@optimizer_switch = 'semijoin=off';
+
+CREATE TABLE t1 ( f3 int(11), f10 varchar(1), f11 varchar(1)) ;
+INSERT IGNORE INTO t1 VALUES (6,'f','f'),(2,'d','d');
+
+CREATE TABLE t2 ( f12 int(11), f13 int(11)) ;
+insert into t2 values (1,2), (3,4);
+
+EXPLAIN
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+        SELECT alias2.f3
+        FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
+        WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
+);
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+        SELECT alias2.f3
+        FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
+        WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
+);
+
+EXPLAIN
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+        SELECT alias2.f3
+        FROM t1 AS alias1, t1 AS alias2
+        WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+SELECT * FROM t2
+WHERE ( f12 ) IN (
+        SELECT alias2.f3
+        FROM t1 AS alias1, t1 AS alias2
+        WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+
+set @@optimizer_switch=@save_optimizer_switch;
+drop table t1, t2;
diff --git a/mysql-test/t/subselect_mat.test b/mysql-test/t/subselect_mat.test
index c18585d0478..90ece548b58 100644
--- a/mysql-test/t/subselect_mat.test
+++ b/mysql-test/t/subselect_mat.test
@@ -48,7 +48,7 @@ insert into t2i select * from t2;
 insert into t3i select * from t3;
 
 # force the use of materialization
-set @@optimizer_switch='semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 
 /******************************************************************************
 * Simple tests.
@@ -111,22 +111,22 @@ select * from t1 where (a1, a2) in (select b1, min(b2) from t2i limit 1,1);
 
 # test re-optimization/re-execution with different execution methods
 # prepare once, exec with different modes
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=on';
 prepare st1 from
 "select * from t1 where (a1, a2) in (select b1, min(b2) from t2 where b1 > '0' group by b1)";
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=on';
 execute st1;
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=on';
 execute st1;
 
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=on';
 prepare st1 from
 "select * from t1 where (a1, a2) in (select b1, min(b2) from t2 where b1 > '0' group by b1)";
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 execute st1;
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=on';
 execute st1;
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 
 # materialize the result of ORDER BY
 # non-indexed fields
@@ -327,7 +327,7 @@ select * from t1 order by (select col from columns limit 1);
   Test that BLOBs are not materialized (except when arguments of some functions).
 */
 # force materialization to be always considered
-set @@optimizer_switch='semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 set @prefix_len = 6;
 
 # BLOB == 16 (small blobs that could be stored in HEAP tables)
@@ -680,7 +680,7 @@ insert into t2bit values (b'001', b'101');
 insert into t2bit values (b'010', b'110');
 insert into t2bit values (b'110', b'111');
 
-set @@optimizer_switch='semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 
 explain extended select bin(a1), bin(a2)
 from t1bit
@@ -718,7 +718,7 @@ drop table t1, t2, t3, t1i, t2i, t3i, columns;
 /******************************************************************************
 * Test the cache of the left operand of IN.
 ******************************************************************************/
-set @@optimizer_switch='semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 
 # Test that default values of Cached_item are not used for comparison
 create table t1 (s1 int);
@@ -812,23 +812,28 @@ drop table t2;
 create table t1 (a1 int key);
 create table t2 (b1 int);
 insert into t1 values (5);
-
+-- echo Only the last query returns correct result. Filed as BUG#40037.
 # Query with group by, executed via materialization
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 explain select min(a1) from t1 where 7 in (select b1 from t2 group by b1);
 select min(a1) from t1 where 7 in (select b1 from t2 group by b1);
 # Query with group by, executed via IN=>EXISTS
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
 explain select min(a1) from t1 where 7 in (select b1 from t2 group by b1);
 select min(a1) from t1 where 7 in (select b1 from t2 group by b1);
 
 # Executed with materialization
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
+explain select min(a1) from t1 where 7 in (select b1 from t2);
+select min(a1) from t1 where 7 in (select b1 from t2);
+# Executed via IN=>EXISTS
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
 explain select min(a1) from t1 where 7 in (select b1 from t2);
 select min(a1) from t1 where 7 in (select b1 from t2);
 # Executed with semi-join. Notice, this time we get a different result (NULL).
-# This is the only correct result of all four queries. This difference is
+# This is the only correct result of all five queries. This difference is
 # filed as BUG#40037.
-set @@optimizer_switch='default,materialization=off';
+set @@optimizer_switch='materialization=off,in_to_exists=off,semijoin=on';
 explain select min(a1) from t1 where 7 in (select b1 from t2);
 select min(a1) from t1 where 7 in (select b1 from t2);
 drop table t1,t2;
@@ -840,7 +845,7 @@ create table t1 (a char(2), b varchar(10));
 insert into t1 values ('a',  'aaa');
 insert into t1 values ('aa', 'aaaa');
 
-set @@optimizer_switch='default,semijoin=off';
+set @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=off';
 explain select a,b from t1 where b in (select a from t1);
 select a,b from t1 where b in (select a from t1);
 prepare st1 from "select a,b from t1 where b in (select a from t1)";
@@ -861,7 +866,7 @@ CREATE TABLE t2 LIKE t1;
 INSERT INTO t2 VALUES (1, 1.789);
 INSERT INTO t2 VALUES (13, 1.454);
 
-SET @@optimizer_switch='default,semijoin=on,materialization=on';
+SET @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=on';
 EXPLAIN SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
 SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
 
@@ -883,7 +888,7 @@ INSERT INTO t1 VALUES (1,'o','ffff','ffff','ffoo'),(2,'f','ffff','ffff','ffff');
 CREATE TABLE t2 LIKE t1;
 INSERT INTO t2 VALUES (1,'i','iiii','iiii','iiii'),(2,'f','ffff','ffff','ffff');
 
-SET @@optimizer_switch='default,semijoin=on,materialization=on';
+SET @@optimizer_switch='materialization=on,in_to_exists=off,semijoin=on';
 EXPLAIN SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 SELECT pk FROM t1 WHERE (b,c,d) IN (SELECT b,c,d FROM t2 WHERE pk > 0);
@@ -900,7 +905,7 @@ create table t3(i int);
 insert into t3 values (1), (2), (3), (4), (5), (6), (7), (8), (9), (10);
 select * from t1 where t1.i in (select t2.i from t2 join t3 where t2.i + t3.i = 5);
 set @save_optimizer_switch=@@optimizer_switch;
-set session optimizer_switch='materialization=off';
+set session optimizer_switch='materialization=off,in_to_exists=on';
 select * from t1 where t1.i in (select t2.i from t2 join t3 where t2.i + t3.i = 5);
 set session optimizer_switch=@save_optimizer_switch;
 drop table t1, t2, t3;
@@ -1022,21 +1027,23 @@ CREATE TABLE t2 ( f2 int);
 INSERT IGNORE INTO t2 VALUES (3),(4);
 CREATE TABLE t3 (f3a int, f3b int);
 
-set session optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off';
+set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,in_to_exists=off';
 
 EXPLAIN
 SELECT * FROM t2 WHERE (SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1);
 SELECT * FROM t2 WHERE (SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1);
 
 EXPLAIN
-SELECT * FROM t2 WHERE (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
-SELECT * FROM t2 WHERE (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
-
-insert into t3 values (1,1),(2,2);
+SELECT (SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1);
+SELECT (SELECT f3a FROM t3) NOT IN (SELECT f1a FROM t1);
 
 EXPLAIN
-SELECT * FROM t2 WHERE (SELECT f3a FROM t3 where f3a > 3) NOT IN (SELECT f1a FROM t1);
-SELECT * FROM t2 WHERE (SELECT f3a FROM t3 where f3a > 3) NOT IN (SELECT f1a FROM t1);
+SELECT * FROM t2 WHERE (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
+SELECT * FROM t2 WHERE (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
+
+EXPLAIN
+SELECT (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
+SELECT (SELECT f3a, f3b FROM t3) NOT IN (SELECT f1a, f1b FROM t1);
 
 drop table t1, t2, t3;
 
@@ -1051,7 +1058,7 @@ CREATE TABLE t2 (f1 int NOT NULL, f2 int, f3 int) ;
 INSERT INTO t1 VALUES (60, 3, null), (61, null, 77);
 INSERT INTO t2 VALUES (1000,6,2);
 
-set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off';
+set @@optimizer_switch='materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off,in_to_exists=off';
 
 EXPLAIN
 SELECT (f1, f2, f3) NOT IN
diff --git a/mysql-test/t/subselect_mat_cost.test b/mysql-test/t/subselect_mat_cost.test
new file mode 100644
index 00000000000..ced99bccea3
--- /dev/null
+++ b/mysql-test/t/subselect_mat_cost.test
@@ -0,0 +1,204 @@
+#
+# Tets of cost-based choice between the materialization and in-to-exists
+# subquery execution strategies (MWL#89)
+#
+
+--disable_warnings
+drop table if exists t1, t2, t1_1024, t2_1024;
+drop procedure if exists make_t1_indexes;
+drop procedure if exists make_t2_indexes;
+drop procedure if exists remove_t1_indexes;
+drop procedure if exists remove_t2_indexes;
+drop procedure if exists add_materialization_data;
+drop procedure if exists delete_materialization_data;
+drop procedure if exists set_all_columns_not_null;
+drop procedure if exists set_all_columns_nullable;
+--enable_warnings
+
+create table t1 (a1 char(8), a2 char(8), a3 char(8), a4 int);
+insert into t1 values ('1 - 00', '2 - 00', '3 - 00', 0);
+insert into t1 values ('1 - 01', '2 - 01', '3 - 01', 1);
+
+create table t2 (b1 char(8), b2 char(8), b3 char(8), b4 int);
+insert into t2 values ('1 - 01', '2 - 01', '3 - 01', 1);
+insert into t2 values ('1 - 01', '2 - 01', '3 - 02', 2);
+insert into t2 values ('1 - 02', '2 - 02', '3 - 03', 3);
+insert into t2 values ('1 - 02', '2 - 02', '3 - 04', 4);
+insert into t2 values ('1 - 03', '2 - 03', '3 - 05', 5);
+
+create table t1_1024 (a1 blob(1024), a2 blob(1024));
+insert into t1_1024 values (concat('1 - 00', repeat('x', 1018)), concat('2 - 00', repeat('x', 1018)));
+insert into t1_1024 values (concat('1 - 01', repeat('x', 1018)), concat('2 - 01', repeat('x', 1018)));
+
+create table t2_1024 (b1 blob(1024), b2 blob(1024));
+insert into t2_1024 values (concat('1 - 01', repeat('x', 1018)), concat('2 - 01', repeat('x', 1018)));
+insert into t2_1024 values (concat('1 - 02', repeat('x', 1018)), concat('2 - 02', repeat('x', 1018)));
+insert into t2_1024 values (concat('1 - 03', repeat('x', 1018)), concat('2 - 03', repeat('x', 1018)));
+insert into t2_1024 values (concat('1 - 04', repeat('x', 1018)), concat('2 - 04', repeat('x', 1018)));
+
+delimiter |;
+create procedure make_t1_indexes()
+begin
+  create index it1i1 on t1 (a1);
+  create index it1i2 on t1 (a2);
+  create index it1i3 on t1 (a1, a2);
+  create index it1_1024i1 on t1_1024 (a1(6));
+  create index it1_1024i2 on t1_1024 (a2(6));
+  create index it1_1024i3 on t1_1024 (a1(6), a2(6));
+end|
+
+create procedure make_t2_indexes()
+begin
+  create index it2i1 on t2 (b1);
+  create index it2i2 on t2 (b2);
+  create index it2i3 on t2 (b1, b2);
+  create unique index it2i4 on t2 (b1, b2, b3);
+  create index it2_1024i1 on t2_1024 (b1(6));
+  create index it2_1024i2 on t2_1024 (b2(6));
+  create index it2_1024i3 on t2_1024 (b1(6), b2(6));
+end|
+
+create procedure remove_t1_indexes()
+begin
+  drop index it1i1 on t1;
+  drop index it1i2 on t1;
+  drop index it1i3 on t1;
+  drop index it1_1024i1 on t1_1024;
+  drop index it1_1024i2 on t1_1024;
+  drop index it1_1024i3 on t1_1024;
+end|
+
+create procedure remove_t2_indexes()
+begin
+  drop index it2i1 on t2;
+  drop index it2i2 on t2;
+  drop index it2i3 on t2;
+  drop index it2i4 on t2;
+  drop index it2_1024i1 on t2_1024;
+  drop index it2_1024i2 on t2_1024;
+  drop index it2_1024i3 on t2_1024;
+end|
+
+create procedure add_materialization_data()
+begin
+insert into t1 values ('1 - 03', '2 - 03', '3 - 03', 3);
+insert into t1 values ('1 - 04', '2 - 04', '3 - 04', 4);
+insert into t1 values ('1 - 05', '2 - 05', '3 - 05', 5);
+insert into t1 values ('1 - 06', '2 - 06', '3 - 06', 6);
+insert into t1 values ('1 - 07', '2 - 07', '3 - 07', 7);
+insert into t1_1024 values (concat('1 - 03', repeat('x', 1018)), concat('2 - 03', repeat('x', 1018)));
+end|
+
+create procedure delete_materialization_data()
+begin
+delete from t1 where a1 >= '1 - 03';
+delete from t1_1024 where a1 >= '1 - 03';
+end|
+
+create procedure set_all_columns_not_null()
+begin
+alter table t1 modify a1 char(8) not null, modify a2 char(8) not null, modify a3 char(8) not null;
+alter table t2 modify b1 char(8) not null, modify b2 char(8) not null, modify b3 char(8) not null;
+end|
+
+create procedure set_all_columns_nullable()
+begin
+alter table t1 modify a1 char(8) null, modify a2 char(8) null, modify a3 char(8) null;
+alter table t2 modify b1 char(8) null, modify b2 char(8) null, modify b3 char(8) null;
+end|
+
+delimiter ;|
+-- echo
+
+-- echo /******************************************************************************
+-- echo 1. Both materialization and in-to-exists are ON, make a cost-based choice.
+-- echo ******************************************************************************/
+set @@optimizer_switch='materialization=on,in_to_exists=on';
+-- echo 
+-- echo /* 1.1 In-to-exists is cheaper */
+call make_t1_indexes();
+
+-- echo /* 1.1.1 non-indexed table access */
+-- source include/subselect_mat_cost.inc
+
+-- echo /* 1.1.2 indexed table access, nullabale columns. */
+call make_t2_indexes();
+-- source include/subselect_mat_cost.inc
+
+-- echo /* 1.1.3 indexed table access, non-nullabale columns. */
+call set_all_columns_not_null();
+-- source include/subselect_mat_cost.inc
+call set_all_columns_nullable();
+
+-- echo 
+-- echo /* 1.2 Materialization is cheaper */
+# make materialization cheaper
+call add_materialization_data();
+call remove_t1_indexes();
+
+-- echo /* 1.2.1 non-indexed table access */
+call remove_t2_indexes();
+-- source include/subselect_mat_cost.inc
+
+-- echo /* 1.2.2 indexed table access, nullabale columns. */
+call make_t2_indexes();
+-- source include/subselect_mat_cost.inc
+
+-- echo /* 1.2.3 indexed table access, non-nullabale columns. */
+call set_all_columns_not_null();
+-- source include/subselect_mat_cost.inc
+call set_all_columns_nullable();
+
+
+insert into t1 values ('1 - 02', '2 - 02', '3 - 02', 2);
+
+-- echo /******************************************************************************
+-- echo 2. Materialization is OFF, in-to-exists is ON, materialization is cheaper.
+-- echo ******************************************************************************/
+set @@optimizer_switch='materialization=off,in_to_exists=on';
+
+-- echo /* 2.1 non-indexed table access */
+call remove_t2_indexes();
+-- source include/subselect_mat_cost.inc
+
+-- echo /* 2.2 indexed table access, nullabale columns. */
+call make_t2_indexes();
+-- source include/subselect_mat_cost.inc
+
+-- echo /* 2.3 indexed table access, non-nullabale columns. */
+call set_all_columns_not_null();
+-- source include/subselect_mat_cost.inc
+call set_all_columns_nullable();
+
+
+-- echo /******************************************************************************
+-- echo 3. Materialization is ON, in-to-exists is OFF, in-to-exists is cheaper.
+-- echo ******************************************************************************/
+set @@optimizer_switch='materialization=on,in_to_exists=off';
+# make IN-TO-EXISTS cheaper
+call delete_materialization_data();
+call make_t1_indexes();
+
+-- echo /* 3.1 non-indexed table access */
+call remove_t2_indexes();
+-- source include/subselect_mat_cost.inc
+
+-- echo /* 3.2 indexed table access, nullabale columns. */
+call make_t2_indexes();
+-- source include/subselect_mat_cost.inc
+
+-- echo /* 3.3 indexed table access, non-nullabale columns. */
+call set_all_columns_not_null();
+-- source include/subselect_mat_cost.inc
+call set_all_columns_nullable();
+
+
+drop procedure make_t1_indexes;
+drop procedure make_t2_indexes;
+drop procedure remove_t1_indexes;
+drop procedure remove_t2_indexes;
+drop procedure add_materialization_data;
+drop procedure delete_materialization_data;
+drop procedure set_all_columns_not_null;
+drop procedure set_all_columns_nullable;
+drop table t1, t2, t1_1024, t2_1024;
diff --git a/mysql-test/t/subselect_mat_cost_bugs.test b/mysql-test/t/subselect_mat_cost_bugs.test
new file mode 100644
index 00000000000..bc052ea04b1
--- /dev/null
+++ b/mysql-test/t/subselect_mat_cost_bugs.test
@@ -0,0 +1,311 @@
+#
+# Test cases for bugs related to the implementation of
+# MWL#89 cost-based choice between the materialization and in-to-exists
+#
+
+--echo #
+--echo # LP BUG#643424 valgrind warning in choose_subquery_plan()
+--echo #
+
+CREATE TABLE t1 (
+  pk int(11) NOT NULL AUTO_INCREMENT,
+  c1 int(11) DEFAULT NULL,
+  c2 int(11) DEFAULT NULL,
+  PRIMARY KEY (pk),
+  KEY c2 (c2));
+
+INSERT INTO t1 VALUES (1,NULL,2);
+INSERT INTO t1 VALUES (2,7,9);
+INSERT INTO t1 VALUES (9,NULL,8);
+
+CREATE TABLE t2 (
+  pk int(11) NOT NULL AUTO_INCREMENT,
+  c1 int(11) DEFAULT NULL,
+  c2 int(11) DEFAULT NULL,
+  PRIMARY KEY (pk),
+  KEY c2 (c2));
+
+INSERT INTO t2 VALUES (1,1,7);
+
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
+
+SELECT pk FROM t1 WHERE (c2, c1) IN (SELECT c2, c2 FROM t2);
+
+set session optimizer_switch=@save_optimizer_switch;
+
+drop table t1, t2;
+
+
+--echo #
+--echo # LP BUG#652727 Crash in create_ref_for_key()
+--echo #
+
+CREATE TABLE t2 (
+  pk int(11) NOT NULL AUTO_INCREMENT,
+  c1 int(11) DEFAULT NULL,
+  PRIMARY KEY (pk));
+
+INSERT INTO t2 VALUES (10,7);
+INSERT INTO t2 VALUES (11,1);
+INSERT INTO t2 VALUES (17,NULL);
+
+CREATE TABLE t1 (
+  pk int(11) NOT NULL AUTO_INCREMENT,
+  c1 int(11) DEFAULT NULL,
+  PRIMARY KEY (pk));
+
+INSERT INTO t1 VALUES (15,1);
+INSERT INTO t1 VALUES (19,NULL);
+
+CREATE TABLE t3 (c2 int(11) DEFAULT NULL, KEY c2 (c2));
+INSERT INTO t3 VALUES (1);
+
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
+
+SELECT c2
+FROM t3
+WHERE (2, 6) IN (SELECT t1.c1, t1.c1 FROM t1 STRAIGHT_JOIN t2 ON t2.pk = t1.pk);
+
+set session optimizer_switch=@save_optimizer_switch;
+drop table t1, t2, t3;
+
+
+--echo #
+--echo # LP BUG#641245 Crash in Item_equal::contains
+--echo #
+
+CREATE TABLE t1 (
+  pk int(11) NOT NULL AUTO_INCREMENT,
+  c1 int(11) DEFAULT NULL,
+  c2 int(11) DEFAULT NULL,
+  c3 varchar(1) DEFAULT NULL,
+  c4 varchar(1) DEFAULT NULL,
+  PRIMARY KEY (pk),
+  KEY c2 (c2),
+  KEY c3 (c3,c2));
+
+INSERT INTO t1 VALUES (10,7,8,'v','v');
+INSERT INTO t1 VALUES (11,1,9,'r','r');
+INSERT INTO t1 VALUES (12,5,9,'a','a');
+
+create table t1a like t1;
+insert into t1a select * from t1;
+
+create table t1b like t1;
+insert into t1b select * from t1;
+
+CREATE TABLE t2 (
+  pk int(11) NOT NULL AUTO_INCREMENT,
+  c1 int(11) DEFAULT NULL,
+  c2 int(11) DEFAULT NULL,
+  c3 varchar(1) DEFAULT NULL,
+  c4 varchar(1) DEFAULT NULL,
+  PRIMARY KEY (pk),
+  KEY c2 (c2),
+  KEY c3 (c3,c2));
+
+INSERT INTO t2 VALUES (1,NULL,2,'w','w');
+INSERT INTO t2 VALUES (2,7,9,'m','m');
+
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
+
+let $query=
+SELECT pk
+FROM t1
+WHERE c1 IN
+      (SELECT t1a.c1
+       FROM (t1b JOIN t2 ON t2.c3 = t1b.c4) LEFT JOIN
+            t1a ON (t1a.c2 = t1b.pk AND 2)
+       WHERE t1.pk) ;
+eval EXPLAIN EXTENDED $query;
+eval $query;
+
+DROP TABLE t1, t1a, t1b, t2;
+
+--echo #
+--echo # LP BUG#714808 Assertion `outer_lookup_keys <= outer_record_count'
+--echo # failed with materialization
+
+CREATE TABLE t1 ( pk int(11), PRIMARY KEY (pk)) ;
+CREATE TABLE t2 ( f2 int(11)) ;
+CREATE TABLE t3 ( f1 int(11), f3 varchar(1), KEY (f1)) ;
+INSERT INTO t3 VALUES (7,'f');
+
+set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
+
+EXPLAIN
+SELECT t1.*
+FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
+WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
+
+SELECT t1.*
+FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
+WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
+
+drop table t1,t2,t3;
+
+--echo #
+--echo # LP BUG#714999 Second crash in select_describe() with nested subqueries
+--echo #
+
+CREATE TABLE t1 ( pk int(11)) ;
+INSERT INTO t1 VALUES (29);
+
+CREATE TABLE t2 ( f1 varchar(1)) ;
+INSERT INTO t2 VALUES ('f'),('d');
+
+CREATE TABLE t3 ( f2 varchar(1)) ;
+
+EXPLAIN SELECT f2 FROM t3 WHERE (
+        SELECT MAX( pk ) FROM t1
+        WHERE EXISTS (
+                SELECT DISTINCT f1
+                FROM t2
+        )
+) IS NULL ;
+
+drop table t1, t2, t3;
+
+--echo #
+--echo # LP BUG#715034 Item_sum_distinct::clear(): Assertion `tree != 0' failed
+--echo #
+
+CREATE TABLE t2 ( f2 int(11)) ;
+
+CREATE TABLE t1 ( f3 int(11), KEY (f3)) ;
+INSERT INTO t1 VALUES (6),(4);
+
+EXPLAIN
+SELECT * FROM (SELECT * FROM t2) AS a2
+WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
+
+insert into t2 values (1),(2);
+EXPLAIN
+SELECT * FROM (SELECT * FROM t2) AS a2
+WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
+
+drop table t1,t2;
+
+--echo #
+--echo # LP BUG#715027 Assertion `!table || (!table->read_set || bitmap_is_set(table->read_set, field_index))' failed
+--echo #
+
+CREATE TABLE t1 ( f1 int(11), PRIMARY KEY (f1)) ;
+INSERT INTO t1 VALUES (28),(29);
+
+CREATE TABLE t2 ( f2 int(11), f3 int(11), f10 varchar(1)) ;
+INSERT INTO t2 VALUES (NULL,6,'f'),(4,2,'d');
+
+EXPLAIN
+SELECT alias2.f2 AS field1
+FROM t1 AS alias1 JOIN ( SELECT * FROM t2 ) AS alias2 ON alias2.f3 = alias1.f1
+WHERE (
+        SELECT t2.f2
+        FROM t2 JOIN t1 ON t1.f1
+        WHERE t1.f1 AND alias2.f10
+)
+ORDER BY field1 ;
+
+SELECT alias2.f2 AS field1
+FROM t1 AS alias1 JOIN ( SELECT * FROM t2 ) AS alias2 ON alias2.f3 = alias1.f1
+WHERE (
+        SELECT t2.f2
+        FROM t2 JOIN t1 ON t1.f1
+        WHERE t1.f1 AND alias2.f10
+)
+ORDER BY field1 ;
+
+drop table t1,t2;
+
+--echo #
+--echo # LP BUG#718578 Yet another Assertion `!table ||
+--echo # (!table->read_set || bitmap_is_set(table->read_set, field_index))'
+
+CREATE TABLE t1 ( f1 int(11), f2 int(11), f3 int(11)) ;
+INSERT IGNORE INTO t1 VALUES (28,5,6),(29,NULL,4);
+
+CREATE TABLE t2 ( f10 varchar(1) );
+INSERT IGNORE INTO t2 VALUES (NULL);
+
+SELECT f1 AS field1
+FROM ( SELECT * FROM t1 ) AS alias1
+WHERE (SELECT t1.f1
+        FROM t2 JOIN t1 ON t1.f2
+        WHERE alias1.f3 AND t1.f3) AND f2
+ORDER BY field1;
+
+drop table t1,t2;
+
+--echo #
+--echo # LP BUG#601124 Bug in eliminate_item_equal
+--echo # leads to crash in Item_func::Item_func
+
+CREATE TABLE t1 ( f1 int(11), f3 varchar(1)) ;
+INSERT INTO t1 VALUES (5,'m'),(NULL,'c');
+
+CREATE TABLE t2 ( f2 int(11), f3 varchar(1)) ;
+INSERT INTO t2 VALUES (6,'f'),(2,'d');
+
+CREATE TABLE t3 ( f2 int(11), f3 varchar(1)) ;
+INSERT INTO t3 VALUES (6,'f'),(2,'d');
+
+SELECT * FROM t3
+WHERE ( f2 ) IN (SELECT t1.f1
+                 FROM t1 STRAIGHT_JOIN t2 ON t2.f3 = t1.f3
+                 WHERE t2.f3 = 'c');
+drop table t1,t2,t3;
+
+
+--echo #
+--echo # LP BUG#718593 Crash in substitute_for_best_equal_field ->
+--echo # eliminate_item_equal -> Item_field::find_item_equal -> Item_equal::contains
+
+--disable_parsing # not yet fixed
+
+CREATE TABLE t1 ( f3 int(11), f10 varchar(1), f11 varchar(1)) ;
+INSERT IGNORE INTO t1 VALUES (6,'f','f'),(2,'d','d');
+
+CREATE TABLE t2 ( f12 int(11), f13 int(11)) ;
+
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
+
+EXPLAIN
+SELECT * FROM t2
+WHERE (f12) IN (
+      SELECT alias2.f3
+      FROM t1 AS alias1, t1 AS alias2
+      WHERE (alias2.f10 = alias1.f11) AND
+             (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+
+SELECT * FROM t2
+WHERE (f12) IN (
+      SELECT alias2.f3
+      FROM t1 AS alias1, t1 AS alias2
+      WHERE (alias2.f10 = alias1.f11) AND
+             (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+
+insert into t2 values (1,2), (3,4);
+
+EXPLAIN
+SELECT * FROM t2
+WHERE (f12) IN (
+      SELECT alias2.f3
+      FROM t1 AS alias1, t1 AS alias2
+      WHERE (alias2.f10 = alias1.f11) AND
+             (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+
+SELECT * FROM t2
+WHERE (f12) IN (
+      SELECT alias2.f3
+      FROM t1 AS alias1, t1 AS alias2
+      WHERE (alias2.f10 = alias1.f11) AND
+             (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
+
+set session optimizer_switch=@save_optimizer_switch;
+
+drop table t1, t2;
+
+--enable_parsing
diff --git a/mysql-test/t/subselect_no_opts.test b/mysql-test/t/subselect_no_opts.test
index a26e8dd4c0d..d72deab45bf 100644
--- a/mysql-test/t/subselect_no_opts.test
+++ b/mysql-test/t/subselect_no_opts.test
@@ -1,6 +1,6 @@
 # 
-# Run subselect.test without semi-join optimization (test materialize)
-#
+# Run subselect.test without semi-join and materialization optimizations
+#  (test in-to-exists)
 set optimizer_switch='materialization=off,semijoin=off';
 
 --source t/subselect.test
diff --git a/mysql-test/t/subselect_sj.test b/mysql-test/t/subselect_sj.test
index acc37a6f9ae..81f92b479e0 100644
--- a/mysql-test/t/subselect_sj.test
+++ b/mysql-test/t/subselect_sj.test
@@ -311,7 +311,7 @@ FROM t0
 WHERE varchar_nokey  IN (  
   SELECT t1 .varchar_key  from t1
 );
-
+--disable_parsing # wrong duplicate results - LP BUG#702374
 SELECT t0.int_key  
 FROM t0
 WHERE t0.varchar_nokey  IN (  
@@ -325,7 +325,7 @@ WHERE t0.varchar_nokey  IN (
   SELECT t1_1 .varchar_key  
   FROM t1 AS t1_1  JOIN t1 AS t1_2 ON t1_1 .int_key  
 );
-
+--enable_parsing
 DROP TABLE t0, t1, t2;
 
 --echo # End of bug#46550
diff --git a/mysql-test/t/subselect_sj2_mat.test b/mysql-test/t/subselect_sj2_mat.test
new file mode 100644
index 00000000000..643a287a897
--- /dev/null
+++ b/mysql-test/t/subselect_sj2_mat.test
@@ -0,0 +1,9 @@
+# 
+# Run subselect_sj2.test with subquery materialization.
+#
+set optimizer_switch='materialization=on';
+
+--source t/subselect_sj2.test
+
+set optimizer_switch=default;
+select @@optimizer_switch like '%materialization=on%';
diff --git a/sql/filesort.cc b/sql/filesort.cc
index 6e3bf27afcc..2b39e74b8cb 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -612,10 +612,34 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
       }
       DBUG_RETURN(HA_POS_ERROR);		/* purecov: inspected */
     }
+
+    bool write_record= false;
     if (error == 0)
+    {
       param->examined_rows++;
-   
-    if (error == 0 && (!select || select->skip_record(thd) > 0))
+      if (select && select->cond)
+      {
+        /*
+          If the condition 'select->cond' contains a subquery, restore the
+          original read/write sets of the table 'sort_form' because when
+          SQL_SELECT::skip_record evaluates this condition. it may include a
+          correlated subquery predicate, such that some field in the subquery
+          refers to 'sort_form'.
+        */
+        if (select->cond->with_subselect)
+          sort_form->column_bitmaps_set(save_read_set, save_write_set,
+                                        save_vcol_set);
+        write_record= (select->skip_record(thd) > 0);
+        if (select->cond->with_subselect)
+          sort_form->column_bitmaps_set(&sort_form->tmp_set,
+                                        &sort_form->tmp_set,
+                                        &sort_form->tmp_set);
+      }
+      else
+        write_record= true;
+    }
+
+    if (write_record)
     {
       if (idx == param->keys)
       {
@@ -628,7 +652,7 @@ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
     }
     else
       file->unlock_row();
-      
+
     /* It does not make sense to read more keys in case of a fatal error */
     if (thd->is_error())
       break;
diff --git a/sql/item.cc b/sql/item.cc
index b0530f0e17e..0b91d4eae9f 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -387,6 +387,8 @@ Item::Item():
   decimals= 0; max_length= 0;
   with_subselect= 0;
   cmp_context= IMPOSSIBLE_RESULT;
+   /* Initially this item is not attached to any JOIN_TAB. */
+  join_tab_idx= MAX_TABLES;
 
   /* Put item in free list so that we can free all items at end */
   THD *thd= current_thd;
@@ -415,6 +417,7 @@ Item::Item():
   tables.
 */
 Item::Item(THD *thd, Item *item):
+  join_tab_idx(item->join_tab_idx),
   is_expensive_cache(-1),
   rsize(0),
   str_value(item->str_value),
@@ -474,6 +477,7 @@ void Item::cleanup()
   DBUG_PRINT("enter", ("this: %p", this));
   fixed=0;
   marker= 0;
+  join_tab_idx= MAX_TABLES;
   if (orig_name)
     name= orig_name;
   DBUG_VOID_RETURN;
@@ -6718,6 +6722,40 @@ bool Item_direct_ref::get_date(MYSQL_TIME *ltime,uint fuzzydate)
 }
 
 
+Item* Item_direct_ref_to_ident::transform(Item_transformer transformer,
+                                          uchar *argument)
+{
+  DBUG_ASSERT(!current_thd->is_stmt_prepare());
+
+  Item *new_item= ident->transform(transformer, argument);
+  if (!new_item)
+    return 0;
+  DBUG_ASSERT(new_item->type() == FIELD_ITEM || new_item->type() == REF_ITEM);
+
+  if (ident != new_item)
+    current_thd->change_item_tree((Item**)&ident, new_item);
+  return (this->*transformer)(argument);
+}
+
+
+Item* Item_direct_ref_to_ident::compile(Item_analyzer analyzer, uchar **arg_p,
+                                        Item_transformer transformer,
+                                        uchar *arg_t)
+{
+  if (!(this->*analyzer)(arg_p))
+    return 0;
+
+  uchar *arg_v= *arg_p;
+  Item *new_item= ident->compile(analyzer, &arg_v, transformer, arg_t);
+  if (new_item && ident != new_item)
+  {
+    DBUG_ASSERT(new_item->type() == FIELD_ITEM || new_item->type() == REF_ITEM);
+    current_thd->change_item_tree((Item**)&ident, new_item);
+  }
+  return (this->*transformer)(arg_t);
+}
+
+
 Item_cache_wrapper::~Item_cache_wrapper()
 {
   DBUG_ASSERT(expr_cache == 0);
diff --git a/sql/item.h b/sql/item.h
index 120ff358098..84fd4b5ce24 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -494,6 +494,17 @@ class COND_EQUAL;
 class Item {
   Item(const Item &);			/* Prevent use of these */
   void operator=(Item &);
+  /**
+    The index in the JOIN::join_tab array of the JOIN_TAB this Item is attached
+    to. Items are attached (or 'pushed') to JOIN_TABs during optimization by the
+    make_cond_for_table procedure. During query execution, this item is
+    evaluated when the join loop reaches the corresponding JOIN_TAB.
+
+    If the value of join_tab_idx >= MAX_TABLES, this means that there is no
+    corresponding JOIN_TAB.
+  */
+  uint join_tab_idx;
+
 public:
   static void *operator new(size_t size) throw ()
   { return sql_alloc(size); }
@@ -510,7 +521,7 @@ public:
              SUBSELECT_ITEM, ROW_ITEM, CACHE_ITEM, TYPE_HOLDER,
              PARAM_ITEM, TRIGGER_FIELD_ITEM, DECIMAL_ITEM,
              XPATH_NODESET, XPATH_NODESET_CMP,
-             VIEW_FIXER_ITEM, EXPR_CACHE_ITEM};
+             VIEW_FIXER_ITEM, EXPR_CACHE_ITEM, UNKNOWN_ITEM};
 
   enum cond_result { COND_UNDEF,COND_OK,COND_TRUE,COND_FALSE };
 
@@ -970,6 +981,8 @@ public:
   virtual bool register_field_in_read_map(uchar *arg) { return 0; }
   virtual bool enumerate_field_refs_processor(uchar *arg) { return 0; }
   virtual bool mark_as_eliminated_processor(uchar *arg) { return 0; }
+  virtual bool eliminate_subselect_processor(uchar *arg) { return 0; }
+  virtual bool set_fake_select_as_master_processor(uchar *arg) { return 0; }
 
   /* To call bool function for all arguments */
   struct bool_func_call_args
@@ -1202,6 +1215,16 @@ public:
   virtual Item_equal *get_item_equal() { return NULL; }
   virtual void set_item_equal(Item_equal *item_eq) {};
   virtual Item_equal *find_item_equal(COND_EQUAL *cond_equal) { return NULL; }
+  /**
+    Set the join tab index to the minimal (left-most) JOIN_TAB to which this
+    Item is attached.
+  */
+  virtual void set_join_tab_idx(uint join_tab_idx_arg)
+  {
+    if (join_tab_idx_arg < join_tab_idx)
+      join_tab_idx= join_tab_idx_arg;
+  }
+  virtual uint get_join_tab_idx() { return join_tab_idx; }
 };
 
 
@@ -2614,6 +2637,43 @@ public:
   virtual Ref_Type ref_type() { return DIRECT_REF; }
 };
 
+
+/**
+  This class is the same as Item_direct_ref but created to wrap Item_ident
+  before fix_fields() call
+*/
+
+class Item_direct_ref_to_ident :public Item_direct_ref
+{
+  Item_ident *ident;
+public:
+  Item_direct_ref_to_ident(Item_ident *item)
+    :Item_direct_ref(item->context, (Item**)&item, item->table_name, item->field_name,
+                     FALSE)
+  {
+    ident= item;
+    ref= (Item**)&ident;
+  }
+
+  bool fix_fields(THD *thd, Item **it)
+  {
+    DBUG_ASSERT(ident->type() == FIELD_ITEM || ident->type() == REF_ITEM);
+    if ((!ident->fixed && ident->fix_fields(thd, ref)) ||
+        ident->check_cols(1))
+      return TRUE;
+    set_properties();
+    return FALSE;
+  }
+
+  virtual void print(String *str, enum_query_type query_type)
+  { ident->print(str, query_type); }
+
+  virtual Item* transform(Item_transformer transformer, uchar *arg);
+  virtual Item* compile(Item_analyzer analyzer, uchar **arg_p,
+                        Item_transformer transformer, uchar *arg_t);
+};
+
+
 class Expression_cache;
 class Item_cache;
 
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index cc6f2f41982..922fbd61025 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -2072,6 +2072,18 @@ Item *Item_in_optimizer::transform(Item_transformer transformer, uchar *argument
 }
 
 
+bool Item_in_optimizer::is_expensive_processor(uchar *arg)
+{
+  return args[1]->is_expensive_processor(arg);
+}
+
+
+bool Item_in_optimizer::is_expensive()
+{
+  return args[1]->is_expensive();
+}
+
+
 longlong Item_func_eq::val_int()
 {
   DBUG_ASSERT(fixed == 1);
@@ -4739,12 +4751,6 @@ Item *and_expressions(Item *a, Item *b, Item **org_item)
 longlong Item_func_isnull::val_int()
 {
   DBUG_ASSERT(fixed == 1);
-  /*
-    Handle optimization if the argument can't be null
-    This has to be here because of the test in update_used_tables().
-  */
-  if (!used_tables_cache && !with_subselect)
-    return cached_value;
   return args[0]->is_null() ? 1: 0;
 }
 
@@ -4752,12 +4758,6 @@ longlong Item_is_not_null_test::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   DBUG_ENTER("Item_is_not_null_test::val_int");
-  if (!used_tables_cache && !with_subselect)
-  {
-    owner->was_null|= (!cached_value);
-    DBUG_PRINT("info", ("cached: %ld", (long) cached_value));
-    DBUG_RETURN(cached_value);
-  }
   if (args[0]->is_null())
   {
     DBUG_PRINT("info", ("null"));
@@ -4774,19 +4774,9 @@ longlong Item_is_not_null_test::val_int()
 void Item_is_not_null_test::update_used_tables()
 {
   if (!args[0]->maybe_null)
-  {
     used_tables_cache= 0;			/* is always true */
-    cached_value= (longlong) 1;
-  }
   else
-  {
     args[0]->update_used_tables();
-    if (!(used_tables_cache=args[0]->used_tables()) && !with_subselect)
-    {
-      /* Remember if the value is always NULL or never NULL */
-      cached_value= (longlong) !args[0]->is_null();
-    }
-  }
 }
 
 
@@ -5464,7 +5454,7 @@ Item *Item_func_nop_all::neg_transformer(THD *thd)
   /* "NOT (e $cmp$ ANY (SELECT ...)) -> e $rev_cmp$" ALL (SELECT ...) */
   Item_func_not_all *new_item= new Item_func_not_all(args[0]);
   Item_allany_subselect *allany= (Item_allany_subselect*)args[0];
-  allany->func= allany->func_creator(FALSE);
+  allany->create_comp_func(FALSE);
   allany->all= !allany->all;
   allany->upper_item= new_item;
   return new_item;
@@ -5476,7 +5466,7 @@ Item *Item_func_not_all::neg_transformer(THD *thd)
   Item_func_nop_all *new_item= new Item_func_nop_all(args[0]);
   Item_allany_subselect *allany= (Item_allany_subselect*)args[0];
   allany->all= !allany->all;
-  allany->func= allany->func_creator(TRUE);
+  allany->create_comp_func(TRUE);
   allany->upper_item= new_item;
   return new_item;
 }
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index 9f4efbc08be..7b7fe29470e 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -266,6 +266,10 @@ public:
   void keep_top_level_cache();
   Item *transform(Item_transformer transformer, uchar *arg);
   virtual Item *expr_cache_insert_transformer(uchar *thd_arg);
+  bool is_expensive_processor(uchar *arg);
+  bool is_expensive();
+  void set_join_tab_idx(uint join_tab_idx_arg)
+  { args[1]->set_join_tab_idx(join_tab_idx_arg); }
 };
 
 class Comp_creator
@@ -1303,8 +1307,6 @@ public:
 
 class Item_func_isnull :public Item_bool_func
 {
-protected:
-  longlong cached_value;
 public:
   Item_func_isnull(Item *a) :Item_bool_func(a) {}
   longlong val_int();
@@ -1322,18 +1324,9 @@ public:
     {
       used_tables_cache= 0;			/* is always false */
       const_item_cache= 1;
-      cached_value= (longlong) 0;
     }
     else
-    {
       args[0]->update_used_tables();
-      if ((const_item_cache= !(used_tables_cache= args[0]->used_tables()) &&
-          !with_subselect))
-      {
-	/* Remember if the value is always NULL or never NULL */
-	cached_value= (longlong) args[0]->is_null();
-      }
-    }
   }
   table_map not_null_tables() const { return 0; }
   optimize_type select_optimize() const { return OPTIMIZE_NULL; }
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 854b328f862..459b025870a 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -36,8 +36,8 @@ Item_subselect::Item_subselect():
   Item_result_field(), value_assigned(0), thd(0), substitution(0),
   expr_cache(0), engine(0), old_engine(0), used_tables_cache(0),
   have_to_be_excluded(0), const_item_cache(1), inside_first_fix_fields(0),
-  done_first_fix_fields(FALSE), eliminated(FALSE), engine_changed(0),
-  changed(0), is_correlated(FALSE)
+  done_first_fix_fields(FALSE), forced_const(FALSE), eliminated(FALSE),
+  engine_changed(0), changed(0), is_correlated(FALSE)
 {
   with_subselect= 1;
   reset();
@@ -123,6 +123,7 @@ void Item_subselect::cleanup()
   reset();
   value_assigned= 0;
   expr_cache= 0;
+  forced_const= FALSE;
   DBUG_VOID_RETURN;
 }
 
@@ -146,7 +147,9 @@ void Item_in_subselect::cleanup()
     left_expr_cache= NULL;
   }
   first_execution= TRUE;
-  is_constant= FALSE;
+  if (in_strategy & SUBS_MATERIALIZATION)
+    in_strategy= 0;
+  pushed_cond_guards= NULL;
   Item_subselect::cleanup();
   DBUG_VOID_RETURN;
 }
@@ -154,13 +157,14 @@ void Item_in_subselect::cleanup()
 Item_subselect::~Item_subselect()
 {
   delete engine;
+  engine= NULL;
 }
 
-Item_subselect::trans_res
+bool
 Item_subselect::select_transformer(JOIN *join)
 {
   DBUG_ENTER("Item_subselect::select_transformer");
-  DBUG_RETURN(RES_OK);
+  DBUG_RETURN(false);
 }
 
 
@@ -195,11 +199,7 @@ bool Item_subselect::fix_fields(THD *thd_param, Item **ref)
   {
     // all transformation is done (used by prepared statements)
     changed= 1;
-  inside_first_fix_fields= FALSE;
-
-
-    // all transformation is done (used by prepared statements)
-    changed= 1;
+    inside_first_fix_fields= FALSE;
 
     /*
       Substitute the current item with an Item_in_optimizer that was
@@ -209,11 +209,14 @@ bool Item_subselect::fix_fields(THD *thd_param, Item **ref)
     */
     if (substitution)
     {
-      // did we changed top item of WHERE condition
+      /*
+        If the top item of the WHERE/HAVING condition changed,
+        set correct WHERE/HAVING for PS.
+      */
       if (unit->outer_select()->where == (*ref))
-	unit->outer_select()->where= substitution; // correct WHERE for PS
+        unit->outer_select()->where= substitution;
       else if (unit->outer_select()->having == (*ref))
-	unit->outer_select()->having= substitution; // correct HAVING for PS
+        unit->outer_select()->having= substitution;
 
       (*ref)= substitution;
       substitution->name= name;
@@ -273,6 +276,69 @@ bool Item_subselect::mark_as_eliminated_processor(uchar *arg)
 }
 
 
+/**
+  Remove a subselect item from its unit so that the unit no longer
+  represents a subquery.
+
+  @param arg  unused parameter
+
+  @return
+    FALSE to force the evaluation of the processor for the subsequent items.
+*/
+
+bool Item_subselect::eliminate_subselect_processor(uchar *arg)
+{
+  unit->item= NULL;
+  unit->exclude_from_tree();
+  eliminated= TRUE;
+  return FALSE;
+}
+
+
+/**
+  Adjust the master select of the subquery to be the fake_select which
+  represents the whole UNION right above the subquery, instead of the
+  last query of the UNION.
+
+  @param arg  pointer to the fake select
+
+  @return
+    FALSE to force the evaluation of the processor for the subsequent items.
+*/
+
+bool Item_subselect::set_fake_select_as_master_processor(uchar *arg)
+{
+  SELECT_LEX *fake_select= (SELECT_LEX*) arg;
+  /*
+    Move the st_select_lex_unit of a subquery from a global ORDER BY clause to
+    become a direct child of the fake_select of a UNION. In this way the
+    ORDER BY that is applied to the temporary table that contains the result of
+    the whole UNION, and all columns in the subquery are resolved against this
+    table. The transformation is applied only for immediate child subqueries of
+    a UNION query.
+  */
+  if (unit->outer_select()->master_unit()->fake_select_lex == fake_select)
+  {
+    /*
+      Set the master of the subquery to be the fake select (i.e. the whole
+      UNION), instead of the last query in the UNION.
+    */
+    fake_select->add_slave(unit);
+    DBUG_ASSERT(unit->outer_select() == fake_select);
+    /* Adjust the name resolution context hierarchy accordingly. */
+    for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
+      sl->context.outer_context= &(fake_select->context);
+    /*
+      Undo Item_subselect::eliminate_subselect_processor because at that phase
+      we don't know yet that the ORDER clause will be moved to the fake select.
+    */
+    unit->item= this;
+    eliminated= FALSE;
+  }
+  return FALSE;
+}
+
+
 bool Item_subselect::mark_as_dependent(THD *thd, st_select_lex *select, 
                                        Item *item)
 {
@@ -548,7 +614,7 @@ bool Item_in_subselect::exec()
     - on a cost-based basis, that takes into account the cost of a cache
       lookup, the cache hit rate, and the savings per cache hit.
   */
-  if (!left_expr_cache && exec_method == MATERIALIZATION)
+  if (!left_expr_cache && (in_strategy & SUBS_MATERIALIZATION))
     init_left_expr_cache();
 
   /*
@@ -601,12 +667,15 @@ Item *Item_subselect::get_tmp_table_item(THD *thd_arg)
 
 void Item_subselect::update_used_tables()
 {
-  recalc_used_tables(parent_select, FALSE);
-  if (!engine->uncacheable())
+  if (!forced_const)
   {
-    // did all used tables become static?
-    if (!(used_tables_cache & ~engine->upper_select_const_tables()))
-      const_item_cache= 1;
+    recalc_used_tables(parent_select, FALSE);
+    if (!engine->uncacheable())
+    {
+      // did all used tables become static?
+      if (!(used_tables_cache & ~engine->upper_select_const_tables()))
+        const_item_cache= 1;
+    }
   }
 }
 
@@ -672,7 +741,7 @@ Item_maxmin_subselect::Item_maxmin_subselect(THD *thd_param,
     of Items belonged to subquery, which will be not repeated
   */
   used_tables_cache= parent->get_used_tables_cache();
-  const_item_cache= parent->get_const_item_cache();
+  const_item_cache= parent->const_item();
 
   /*
     this subquery always creates during preparation, so we can assign
@@ -710,8 +779,7 @@ void Item_maxmin_subselect::print(String *str, enum_query_type query_type)
 
 void Item_singlerow_subselect::reset()
 {
-  eliminated= FALSE;
-  null_value= TRUE;
+  Item_subselect::reset();
   if (value)
     value->null_value= TRUE;
 }
@@ -726,13 +794,17 @@ void Item_singlerow_subselect::reset()
   - switch off this optimization for prepare statement,
   because we do not rollback this changes.
   Make rollback for it, or special name resolving mode in 5.0.
+
+  @param join  Join object of the subquery (i.e. 'child' join).
+
+  @retval false  The subquery was transformed
 */
-Item_subselect::trans_res
+bool
 Item_singlerow_subselect::select_transformer(JOIN *join)
 {
   DBUG_ENTER("Item_singlerow_subselect::select_transformer");
   if (changed)
-    DBUG_RETURN(RES_OK);
+    DBUG_RETURN(false);
 
   SELECT_LEX *select_lex= join->select_lex;
   Query_arena *arena= thd->stmt_arena;
@@ -759,7 +831,6 @@ Item_singlerow_subselect::select_transformer(JOIN *join)
       !arena->is_stmt_prepare_or_first_sp_execute()
       )
   {
-
     have_to_be_excluded= 1;
     if (thd->lex->describe)
     {
@@ -775,9 +846,8 @@ Item_singlerow_subselect::select_transformer(JOIN *join)
     */
     substitution->walk(&Item::remove_dependence_processor, 0,
 		       (uchar *) select_lex->outer_select());
-    DBUG_RETURN(RES_REDUCE);
   }
-  DBUG_RETURN(RES_OK);
+  DBUG_RETURN(false);
 }
 
 
@@ -1008,11 +1078,11 @@ bool Item_in_subselect::test_limit(st_select_lex_unit *unit_arg)
 Item_in_subselect::Item_in_subselect(Item * left_exp,
 				     st_select_lex *select_lex):
   Item_exists_subselect(), left_expr_cache(0), first_execution(TRUE),
-  is_constant(FALSE), optimizer(0), pushed_cond_guards(NULL),
-  exec_method(NOT_TRANSFORMED), upper_item(0)
+  optimizer(0), pushed_cond_guards(NULL), in_strategy(0), upper_item(0)
 {
   DBUG_ENTER("Item_in_subselect::Item_in_subselect");
   left_expr= left_exp;
+  func= &eq_creator;
   init(select_lex, new select_exists_subselect(this));
   max_columns= UINT_MAX;
   maybe_null= 1;
@@ -1239,7 +1309,7 @@ bool Item_in_subselect::val_bool()
 {
   DBUG_ASSERT(fixed == 1);
   null_value= was_null= FALSE;
-  if (is_constant)
+  if (forced_const)
     return value;
   if (exec())
   {
@@ -1272,59 +1342,37 @@ my_decimal *Item_in_subselect::val_decimal(my_decimal *decimal_value)
 }
 
 
-/* 
-  Rewrite a single-column IN/ALL/ANY subselect
+/**
+  Rewrite a single-column IN/ALL/ANY subselect.
 
-  SYNOPSIS
-    Item_in_subselect::single_value_transformer()
-      join  Join object of the subquery (i.e. 'child' join).
-      func  Subquery comparison creator
+  @param join  Join object of the subquery (i.e. 'child' join).
 
-  DESCRIPTION
-    Rewrite a single-column subquery using rule-based approach. The subquery
+  @details
+  Rewrite a single-column subquery using rule-based approach. Given the subquery
+
+     oe $cmp$ (SELECT ie FROM ... WHERE subq_where ... HAVING subq_having)
+
+  First, try to convert the subquery to a scalar-result subquery in one of
+  the forms:
     
-       oe $cmp$ (SELECT ie FROM ... WHERE subq_where ... HAVING subq_having)
-    
-    First, try to convert the subquery to scalar-result subquery in one of
-    the forms:
-    
-       - oe $cmp$ (SELECT MAX(...) )  // handled by Item_singlerow_subselect
-       - oe $cmp$ <max>(SELECT ...)   // handled by Item_maxmin_subselect
+     - oe $cmp$ (SELECT MAX(...) )  // handled by Item_singlerow_subselect
+     - oe $cmp$ <max>(SELECT ...)   // handled by Item_maxmin_subselect
+
+  If that fails, check if the subquery is a single select without tables,
+  and substitute the subquery predicate with "oe $cmp$ ie".
    
-    If that fails, the subquery will be handled with class Item_in_optimizer, 
-    Inject the predicates into subquery, i.e. convert it to:
+  If that fails, the subquery predicate is wrapped into an Item_in_optimizer.
+  Later the query optimization phase chooses whether the subquery under the
+  Item_in_optimizer will be further transformed into an equivalent correlated
+  EXISTS by injecting additional predicates, or will be executed via subquery
+  materialization in its unmodified form.
 
-    - If the subquery has aggregates, GROUP BY, or HAVING, convert to
-
-       SELECT ie FROM ...  HAVING subq_having AND 
-                                   trigcond(oe $cmp$ ref_or_null_helper<ie>)
-                                   
-      the addition is wrapped into trigger only when we want to distinguish
-      between NULL and FALSE results.
-
-    - Otherwise (no aggregates/GROUP BY/HAVING) convert it to one of the
-      following:
-
-      = If we don't need to distinguish between NULL and FALSE subquery:
-        
-        SELECT 1 FROM ... WHERE (oe $cmp$ ie) AND subq_where
-
-      = If we need to distinguish between those:
-
-        SELECT 1 FROM ...
-          WHERE  subq_where AND trigcond((oe $cmp$ ie) OR (ie IS NULL))
-          HAVING trigcond(<is_not_null_test>(ie))
-
-  RETURN
-    RES_OK     Either subquery was transformed, or appopriate
-                       predicates where injected into it.
-    RES_REDUCE The subquery was reduced to non-subquery
-    RES_ERROR  Error
+  @retval false  The subquery was transformed
+  @retval true   Error
 */
 
-Item_subselect::trans_res
-Item_in_subselect::single_value_transformer(JOIN *join,
-					    Comp_creator *func)
+bool
+Item_in_subselect::single_value_transformer(JOIN *join)
 {
   SELECT_LEX *select_lex= join->select_lex;
   DBUG_ENTER("Item_in_subselect::single_value_transformer");
@@ -1337,7 +1385,7 @@ Item_in_subselect::single_value_transformer(JOIN *join,
   if (select_lex->item_list.elements > 1)
   {
     my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
-    DBUG_RETURN(RES_ERROR);
+    DBUG_RETURN(true);
   }
 
   /*
@@ -1356,8 +1404,8 @@ Item_in_subselect::single_value_transformer(JOIN *join,
   {
     if (substitution)
     {
-      // It is second (third, ...) SELECT of UNION => All is done
-      DBUG_RETURN(RES_OK);
+      /* It is second (third, ...) SELECT of UNION => All is done */
+      DBUG_RETURN(false);
     }
 
     Item *subs;
@@ -1402,7 +1450,7 @@ Item_in_subselect::single_value_transformer(JOIN *join,
         we do not check item->fixed
       */
       if (item->fix_fields(thd, 0))
-	DBUG_RETURN(RES_ERROR);
+	DBUG_RETURN(true);
       thd->lex->allow_sum_func= save_allow_sum_func; 
       /* we added aggregate function => we have to change statistic */
       count_field_types(select_lex, &join->tmp_table_param, join->all_fields, 
@@ -1419,9 +1467,39 @@ Item_in_subselect::single_value_transformer(JOIN *join,
     }
     /* fix fields is already called for  left expression */
     substitution= func->create(left_expr, subs);
-    DBUG_RETURN(RES_OK);
+    DBUG_RETURN(false);
   }
 
+  Item* join_having= join->having ? join->having : join->tmp_having;
+  if (!(join_having || select_lex->with_sum_func ||
+        select_lex->group_list.elements) &&
+      select_lex->table_list.elements == 0 &&
+      !select_lex->master_unit()->is_union())
+  {
+    Item *where_item= (Item*) select_lex->item_list.head();
+    /*
+      it is single select without tables => possible optimization
+      remove the dependence mark since the item is moved to upper
+      select and is not outer anymore.
+    */
+    where_item->walk(&Item::remove_dependence_processor, 0,
+                     (uchar *) select_lex->outer_select());
+    substitution= func->create(left_expr, where_item);
+    have_to_be_excluded= 1;
+    if (thd->lex->describe)
+    {
+      char warn_buff[MYSQL_ERRMSG_SIZE];
+      sprintf(warn_buff, ER(ER_SELECT_REDUCED), select_lex->select_number);
+      push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
+                   ER_SELECT_REDUCED, warn_buff);
+    }
+    DBUG_RETURN(false);
+  }
+
+  /*
+    Wrap the current IN predicate in an Item_in_optimizer. The actual
+    substitution in the Item tree takes place in Item_subselect::fix_fields.
+  */
   if (!substitution)
   {
     /* We're invoked for the 1st (or the only) SELECT in the subquery UNION */
@@ -1435,7 +1513,7 @@ Item_in_subselect::single_value_transformer(JOIN *join,
     if (!optimizer || optimizer->fix_left(thd, 0))
     {
       thd->lex->current_select= current;
-      DBUG_RETURN(RES_ERROR);
+      DBUG_RETURN(true);
     }
     thd->lex->current_select= current;
 
@@ -1462,30 +1540,33 @@ Item_in_subselect::single_value_transformer(JOIN *join,
     select_lex->uncacheable|= UNCACHEABLE_EXPLAIN;
   }
 
-  if (!abort_on_null && left_expr->maybe_null && !pushed_cond_guards)
+  DBUG_RETURN(false);
+}
+
+
+bool Item_in_subselect::fix_having(Item *having, SELECT_LEX *select_lex)
+{
+  bool fix_res= 0;
+  if (!having->fixed)
   {
-    if (!(pushed_cond_guards= (bool*)join->thd->alloc(sizeof(bool))))
-      DBUG_RETURN(RES_ERROR);
-    pushed_cond_guards[0]= TRUE;
+    select_lex->having_fix_field= 1;
+    fix_res= having->fix_fields(thd, 0);
+    select_lex->having_fix_field= 0;
   }
-
-  /*
-    If this IN predicate can be computed via materialization, do not
-    perform the IN -> EXISTS transformation.
-  */
-  if (exec_method == MATERIALIZATION)
-    DBUG_RETURN(RES_OK);
-
-  /* Perform the IN=>EXISTS transformation. */
-  DBUG_RETURN(single_value_in_to_exists_transformer(join, func));
+  return fix_res;
 }
 
 
 /**
-  Transofrm an IN predicate into EXISTS via predicate injection.
+  Create the predicates needed to transform a single-column IN/ALL/ANY
+  subselect into a correlated EXISTS via predicate injection.
 
-  @details The transformation injects additional predicates into the subquery
-  (and makes the subquery correlated) as follows.
+  @param join[in]  Join object of the subquery (i.e. 'child' join).
+  @param where_item[out]   the in-to-exists addition to the where clause
+  @param having_item[out]  the in-to-exists addition to the having clause
+
+  @details
+  The correlated predicates are created as follows:
 
   - If the subquery has aggregates, GROUP BY, or HAVING, convert to
 
@@ -1500,37 +1581,38 @@ Item_in_subselect::single_value_transformer(JOIN *join,
 
     = If we don't need to distinguish between NULL and FALSE subquery:
         
-      SELECT 1 FROM ... WHERE (oe $cmp$ ie) AND subq_where
+      SELECT ie FROM ... WHERE subq_where AND (oe $cmp$ ie)
 
     = If we need to distinguish between those:
 
-      SELECT 1 FROM ...
+      SELECT ie FROM ...
         WHERE  subq_where AND trigcond((oe $cmp$ ie) OR (ie IS NULL))
         HAVING trigcond(<is_not_null_test>(ie))
 
-    @param join  Join object of the subquery (i.e. 'child' join).
-    @param func  Subquery comparison creator
-
-    @retval RES_OK     Either subquery was transformed, or appopriate
-                       predicates where injected into it.
-    @retval RES_REDUCE The subquery was reduced to non-subquery
-    @retval RES_ERROR  Error
+  @retval false If the new conditions were created successfully
+  @retval true  Error
 */
 
-Item_subselect::trans_res
-Item_in_subselect::single_value_in_to_exists_transformer(JOIN * join, Comp_creator *func)
+bool
+Item_in_subselect::create_single_in_to_exists_cond(JOIN * join,
+                                                   Item **where_item,
+                                                   Item **having_item)
 {
   SELECT_LEX *select_lex= join->select_lex;
-  DBUG_ENTER("Item_in_subselect::single_value_in_to_exists_transformer");
-
   /*
-    The IN=>EXISTS transformation makes non-correlated subqueries correlated.
+    The non-transformed HAVING clause of 'join' may be stored in two ways
+    during JOIN::optimize: this->tmp_having= this->having; this->having= 0;
   */
-  select_lex->uncacheable|= UNCACHEABLE_DEPENDENT;
-  if (join->having || select_lex->with_sum_func ||
+  Item* join_having= join->having ? join->having : join->tmp_having;
+
+  DBUG_ENTER("Item_in_subselect::create_single_in_to_exists_cond");
+
+  *where_item= NULL;
+  *having_item= NULL;
+
+  if (join_having || select_lex->with_sum_func ||
       select_lex->group_list.elements)
   {
-    bool tmp;
     Item *item= func->create(expr,
                              new Item_ref_null_helper(&select_lex->context,
                                                       this,
@@ -1546,24 +1628,12 @@ Item_in_subselect::single_value_in_to_exists_transformer(JOIN * join, Comp_creat
       */
       item= new Item_func_trig_cond(item, get_cond_guard(0));
     }
-    
-    /*
-      AND and comparison functions can't be changed during fix_fields()
-      we can assign select_lex->having here, and pass 0 as last
-      argument (reference) to fix_fields()
-    */
-    select_lex->having= join->having= and_items(join->having, item);
-    if (join->having == item)
-      item->name= (char*)in_having_cond;
-    select_lex->having_fix_field= 1;
-    /*
-      we do not check join->having->fixed, because Item_and (from and_items)
-      or comparison function (from func->create) can't be fixed after creation
-    */
-    tmp= join->having->fix_fields(thd, 0);
-    select_lex->having_fix_field= 0;
-    if (tmp)
-      DBUG_RETURN(RES_ERROR);
+
+    if (!join_having)
+      item->name= (char*) in_having_cond;
+    if (fix_having(item, select_lex))
+      DBUG_RETURN(true);
+    *having_item= item;
   }
   else
   {
@@ -1571,13 +1641,8 @@ Item_in_subselect::single_value_in_to_exists_transformer(JOIN * join, Comp_creat
 
     if (select_lex->table_list.elements)
     {
-      bool tmp;
-      Item *having= item, *orig_item= item;
-      select_lex->item_list.empty();
-      select_lex->item_list.push_back(new Item_int("Not_used",
-                                                   (longlong) 1,
-                                                   MY_INT64_NUM_DECIMAL_DIGITS));
-      select_lex->ref_pointer_array[0]= select_lex->item_list.head();
+      Item *having= item;
+      Item *orig_item= item;
        
       item= func->create(expr, item);
       if (!abort_on_null && orig_item->maybe_null)
@@ -1587,25 +1652,13 @@ Item_in_subselect::single_value_in_to_exists_transformer(JOIN * join, Comp_creat
         {
           if (!(having= new Item_func_trig_cond(having,
                                                 get_cond_guard(0))))
-            DBUG_RETURN(RES_ERROR);
+            DBUG_RETURN(true);
         }
-	/*
-	  Item_is_not_null_test can't be changed during fix_fields()
-	  we can assign select_lex->having here, and pass 0 as last
-	  argument (reference) to fix_fields()
-	*/
-        having->name= (char*)in_having_cond;
-	select_lex->having= join->having= having;
-	select_lex->having_fix_field= 1;
-        /*
-          we do not check join->having->fixed, because Item_and (from
-          and_items) or comparison function (from func->create) can't be
-          fixed after creation
-        */
-	tmp= join->having->fix_fields(thd, 0);
-        select_lex->having_fix_field= 0;
-        if (tmp)
-	  DBUG_RETURN(RES_ERROR);
+        having->name= (char*) in_having_cond;
+        if (fix_having(having, select_lex))
+          DBUG_RETURN(true);
+        *having_item= having;
+
 	item= new Item_cond_or(item,
 			       new Item_func_isnull(orig_item));
       }
@@ -1616,39 +1669,23 @@ Item_in_subselect::single_value_in_to_exists_transformer(JOIN * join, Comp_creat
       if (!abort_on_null && left_expr->maybe_null)
       {
         if (!(item= new Item_func_trig_cond(item, get_cond_guard(0))))
-          DBUG_RETURN(RES_ERROR);
+          DBUG_RETURN(true);
       }
+
       /*
         TODO: figure out why the following is done here in 
         single_value_transformer but there is no corresponding action in
         row_value_transformer?
       */
-      item->name= (char *)in_additional_cond;
-
-      /*
-	AND can't be changed during fix_fields()
-	we can assign select_lex->having here, and pass 0 as last
-	argument (reference) to fix_fields()
-      */
-      select_lex->where= join->conds= and_items(join->conds, item);
-      select_lex->where->top_level_item();
-      /*
-        we do not check join->conds->fixed, because Item_and can't be fixed
-        after creation
-      */
-      if (join->conds->fix_fields(thd, 0))
-	DBUG_RETURN(RES_ERROR);
+      item->name= (char *) in_additional_cond;
+      if (!item->fixed && item->fix_fields(thd, 0))
+        DBUG_RETURN(true);
+      *where_item= item;
     }
     else
     {
-      bool tmp;
       if (select_lex->master_unit()->is_union())
       {
-	/*
-	  comparison functions can't be changed during fix_fields()
-	  we can assign select_lex->having here, and pass 0 as last
-	  argument (reference) to fix_fields()
-	*/
         Item *new_having=
           func->create(expr,
                        new Item_ref_null_helper(&select_lex->context, this,
@@ -1659,49 +1696,40 @@ Item_in_subselect::single_value_in_to_exists_transformer(JOIN * join, Comp_creat
         {
           if (!(new_having= new Item_func_trig_cond(new_having,
                                                     get_cond_guard(0))))
-            DBUG_RETURN(RES_ERROR);
+            DBUG_RETURN(true);
         }
-        new_having->name= (char*)in_having_cond;
-	select_lex->having= join->having= new_having;
-	select_lex->having_fix_field= 1;
-        
-        /*
-          we do not check join->having->fixed, because comparison function
-          (from func->create) can't be fixed after creation
-        */
-	tmp= join->having->fix_fields(thd, 0);
-        select_lex->having_fix_field= 0;
-        if (tmp)
-	  DBUG_RETURN(RES_ERROR);
+
+        new_having->name= (char*) in_having_cond;
+        if (fix_having(new_having, select_lex))
+          DBUG_RETURN(true);
+        *having_item= new_having;
       }
       else
-      {
-	// it is single select without tables => possible optimization
-        // remove the dependence mark since the item is moved to upper
-        // select and is not outer anymore.
-        item->walk(&Item::remove_dependence_processor, 0,
-                           (uchar *) select_lex->outer_select());
-	item= func->create(left_expr, item);
-	// fix_field of item will be done in time of substituting
-	substitution= item;
-	have_to_be_excluded= 1;
-	if (thd->lex->describe)
-	{
-	  char warn_buff[MYSQL_ERRMSG_SIZE];
-	  sprintf(warn_buff, ER(ER_SELECT_REDUCED), select_lex->select_number);
-	  push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
-		       ER_SELECT_REDUCED, warn_buff);
-	}
-	DBUG_RETURN(RES_REDUCE);
-      }
+        DBUG_ASSERT(FALSE);
     }
   }
 
-  DBUG_RETURN(RES_OK);
+  DBUG_RETURN(false);
 }
 
 
-Item_subselect::trans_res
+/**
+  Wrap a multi-column IN/ALL/ANY subselect into an Item_in_optimizer.
+
+  @param join  Join object of the subquery (i.e. 'child' join).
+
+  @details
+  The subquery predicate is wrapped into an Item_in_optimizer. Later the query
+  optimization phase chooses whether the subquery under the Item_in_optimizer
+  will be further transformed into an equivalent correlated EXISTS by injecting
+  additional predicates, or will be executed via subquery materialization in its
+  unmodified form.
+
+  @retval false  The subquery was transformed
+  @retval true   Error
+*/
+
+bool
 Item_in_subselect::row_value_transformer(JOIN *join)
 {
   SELECT_LEX *select_lex= join->select_lex;
@@ -1713,7 +1741,7 @@ Item_in_subselect::row_value_transformer(JOIN *join)
   if (select_lex->item_list.elements != cols_num)
   {
     my_error(ER_OPERAND_COLUMNS, MYF(0), cols_num);
-    DBUG_RETURN(RES_ERROR);
+    DBUG_RETURN(true);
   }
 
   /*
@@ -1732,7 +1760,7 @@ Item_in_subselect::row_value_transformer(JOIN *join)
     if (!optimizer || optimizer->fix_left(thd, 0))
     {
       thd->lex->current_select= current;
-      DBUG_RETURN(RES_ERROR);
+      DBUG_RETURN(true);
     }
 
     // we will refer to upper level cache array => we have to save it in PS
@@ -1748,89 +1776,97 @@ Item_in_subselect::row_value_transformer(JOIN *join)
     */
     master_unit->uncacheable|= UNCACHEABLE_EXPLAIN;
     select_lex->uncacheable|= UNCACHEABLE_EXPLAIN;
-
-    if (!abort_on_null && left_expr->maybe_null && !pushed_cond_guards)
-    {
-      if (!(pushed_cond_guards= (bool*)join->thd->alloc(sizeof(bool) *
-                                                        left_expr->cols())))
-        DBUG_RETURN(RES_ERROR);
-      for (uint i= 0; i < cols_num; i++)
-        pushed_cond_guards[i]= TRUE;
-    }
   }
 
-  /*
-    If this IN predicate can be computed via materialization, do not
-    perform the IN -> EXISTS transformation.
-  */
-  if (exec_method == MATERIALIZATION)
-    DBUG_RETURN(RES_OK);
-
-  /* Perform the IN=>EXISTS transformation. */
-  DBUG_RETURN(row_value_in_to_exists_transformer(join));
+  DBUG_RETURN(false);
 }
 
 
 /**
-  Tranform a (possibly non-correlated) IN subquery into a correlated EXISTS.
+  Create the predicates needed to transform a multi-column IN/ALL/ANY
+  subselect into a correlated EXISTS via predicate injection.
 
-  @todo
-  The IF-ELSE below can be refactored so that there is no duplication of the
-  statements that create the new conditions. For this we have to invert the IF
-  and the FOR statements as this:
-  for (each left operand)
-    create the equi-join condition
-    if (is_having_used || !abort_on_null)
-      create the "is null" and is_not_null_test items
-    if (is_having_used)
-      add the equi-join and the null tests to HAVING
-    else
-      add the equi-join and the "is null" to WHERE
-      add the is_not_null_test to HAVING
+  @details
+  The correlated predicates are created as follows:
+
+  - If the subquery has aggregates, GROUP BY, or HAVING, convert to
+
+    (l1, l2, l3) IN (SELECT v1, v2, v3 ... HAVING having)
+    =>
+    EXISTS (SELECT ... HAVING having and
+                              (l1 = v1 or is null v1) and
+                              (l2 = v2 or is null v2) and
+                              (l3 = v3 or is null v3) and
+                              is_not_null_test(v1) and
+                              is_not_null_test(v2) and
+                              is_not_null_test(v3))
+
+    where is_not_null_test used to register nulls in case if we have
+    not found matching to return correct NULL value.
+
+  - Otherwise (no aggregates/GROUP BY/HAVING) convert the subquery as follows:
+
+    (l1, l2, l3) IN (SELECT v1, v2, v3 ... WHERE where)
+    =>
+    EXISTS (SELECT ... WHERE where and
+                             (l1 = v1 or is null v1) and
+                             (l2 = v2 or is null v2) and
+                             (l3 = v3 or is null v3)
+                       HAVING is_not_null_test(v1) and
+                              is_not_null_test(v2) and
+                              is_not_null_test(v3))
+    where is_not_null_test registers NULLs values but reject rows.
+
+    in case when we do not need correct NULL, we have simplier construction:
+    EXISTS (SELECT ... WHERE where and
+                             (l1 = v1) and
+                             (l2 = v2) and
+                             (l3 = v3)
+
+  @param join[in]  Join object of the subquery (i.e. 'child' join).
+  @param where_item[out]   the in-to-exists addition to the where clause
+  @param having_item[out]  the in-to-exists addition to the having clause
+
+  @retval false  If the new conditions were created successfully
+  @retval true   Error
 */
 
-Item_subselect::trans_res
-Item_in_subselect::row_value_in_to_exists_transformer(JOIN * join)
+bool
+Item_in_subselect::create_row_in_to_exists_cond(JOIN * join,
+                                                Item **where_item,
+                                                Item **having_item)
 {
   SELECT_LEX *select_lex= join->select_lex;
-  Item *having_item= 0;
   uint cols_num= left_expr->cols();
-  bool is_having_used= (join->having || select_lex->with_sum_func ||
+  /*
+    The non-transformed HAVING clause of 'join' may be stored in two ways
+    during JOIN::optimize: this->tmp_having= this->having; this->having= 0;
+  */
+  Item* join_having= join->having ? join->having : join->tmp_having;
+  bool is_having_used= (join_having || select_lex->with_sum_func ||
                         select_lex->group_list.first ||
                         !select_lex->table_list.elements);
 
-  DBUG_ENTER("Item_in_subselect::row_value_in_to_exists_transformer");
+  DBUG_ENTER("Item_in_subselect::create_row_in_to_exists_cond");
+
+  *where_item= NULL;
+  *having_item= NULL;
 
-  /*
-    The IN=>EXISTS transformation makes non-correlated subqueries correlated.
-  */
-  select_lex->uncacheable|= UNCACHEABLE_DEPENDENT;
   if (is_having_used)
   {
-    /*
-      (l1, l2, l3) IN (SELECT v1, v2, v3 ... HAVING having) =>
-      EXISTS (SELECT ... HAVING having and
-                                (l1 = v1 or is null v1) and
-                                (l2 = v2 or is null v2) and
-                                (l3 = v3 or is null v3) and
-                                is_not_null_test(v1) and
-                                is_not_null_test(v2) and
-                                is_not_null_test(v3))
-      where is_not_null_test used to register nulls in case if we have
-      not found matching to return correct NULL value
-      TODO: say here explicitly if the order of AND parts matters or not.
-    */
+    /* TODO: say here explicitly if the order of AND parts matters or not. */
     Item *item_having_part2= 0;
     for (uint i= 0; i < cols_num; i++)
     {
       DBUG_ASSERT((left_expr->fixed &&
+
                   select_lex->ref_pointer_array[i]->fixed) ||
                   (select_lex->ref_pointer_array[i]->type() == REF_ITEM &&
                    ((Item_ref*)(select_lex->ref_pointer_array[i]))->ref_type() ==
                     Item_ref::OUTER_REF));
       if (select_lex->ref_pointer_array[i]->
           check_cols(left_expr->element_index(i)->cols()))
-        DBUG_RETURN(RES_ERROR);
+        DBUG_RETURN(true);
       Item *item_eq=
         new Item_func_eq(new
                          Item_ref(&select_lex->context,
@@ -1842,23 +1878,21 @@ Item_in_subselect::row_value_in_to_exists_transformer(JOIN * join)
                          Item_ref(&select_lex->context,
                                   select_lex->ref_pointer_array + i,
                                   (char *)"<no matter>",
-                                  (char *)"<list ref>")
-                        );
+                                  (char *)"<list ref>"));
       Item *item_isnull=
         new Item_func_isnull(new
                              Item_ref(&select_lex->context,
                                       select_lex->ref_pointer_array+i,
                                       (char *)"<no matter>",
-                                      (char *)"<list ref>")
-                            );
+                                      (char *)"<list ref>"));
       Item *col_item= new Item_cond_or(item_eq, item_isnull);
       if (!abort_on_null && left_expr->element_index(i)->maybe_null)
       {
         if (!(col_item= new Item_func_trig_cond(col_item, get_cond_guard(i))))
-          DBUG_RETURN(RES_ERROR);
+          DBUG_RETURN(true);
       }
-      having_item= and_items(having_item, col_item);
-      
+      *having_item= and_items(*having_item, col_item);
+
       Item *item_nnull_test= 
          new Item_is_not_null_test(this,
                                    new Item_ref(&select_lex->context,
@@ -1870,34 +1904,15 @@ Item_in_subselect::row_value_in_to_exists_transformer(JOIN * join)
       {
         if (!(item_nnull_test= 
               new Item_func_trig_cond(item_nnull_test, get_cond_guard(i))))
-          DBUG_RETURN(RES_ERROR);
+          DBUG_RETURN(true);
       }
       item_having_part2= and_items(item_having_part2, item_nnull_test);
       item_having_part2->top_level_item();
     }
-    having_item= and_items(having_item, item_having_part2);
-    having_item->top_level_item();
+    *having_item= and_items(*having_item, item_having_part2);
   }
   else
   {
-    /*
-      (l1, l2, l3) IN (SELECT v1, v2, v3 ... WHERE where) =>
-      EXISTS (SELECT ... WHERE where and
-                               (l1 = v1 or is null v1) and
-                               (l2 = v2 or is null v2) and
-                               (l3 = v3 or is null v3)
-                         HAVING is_not_null_test(v1) and
-                                is_not_null_test(v2) and
-                                is_not_null_test(v3))
-      where is_not_null_test register NULLs values but reject rows
-
-      in case when we do not need correct NULL, we have simplier construction:
-      EXISTS (SELECT ... WHERE where and
-                               (l1 = v1) and
-                               (l2 = v2) and
-                               (l3 = v3)
-    */
-    Item *where_item= 0;
     for (uint i= 0; i < cols_num; i++)
     {
       Item *item, *item_isnull;
@@ -1908,7 +1923,7 @@ Item_in_subselect::row_value_in_to_exists_transformer(JOIN * join)
                     Item_ref::OUTER_REF));
       if (select_lex->ref_pointer_array[i]->
           check_cols(left_expr->element_index(i)->cols()))
-        DBUG_RETURN(RES_ERROR);
+        DBUG_RETURN(true);
       item=
         new Item_func_eq(new
                          Item_direct_ref(&select_lex->context,
@@ -1921,8 +1936,7 @@ Item_in_subselect::row_value_in_to_exists_transformer(JOIN * join)
                                          select_lex->
                                          ref_pointer_array+i,
                                          (char *)"<no matter>",
-                                         (char *)"<list ref>")
-                        );
+                                         (char *)"<list ref>"));
       if (!abort_on_null)
       {
         Item *having_col_item=
@@ -1940,8 +1954,7 @@ Item_in_subselect::row_value_in_to_exists_transformer(JOIN * join)
                                            select_lex->
                                            ref_pointer_array+i,
                                            (char *)"<no matter>",
-                                           (char *)"<list ref>")
-                          );
+                                           (char *)"<list ref>"));
         item= new Item_cond_or(item, item_isnull);
         /* 
           TODO: why we create the above for cases where the right part
@@ -1950,104 +1963,198 @@ Item_in_subselect::row_value_in_to_exists_transformer(JOIN * join)
         if (left_expr->element_index(i)->maybe_null)
         {
           if (!(item= new Item_func_trig_cond(item, get_cond_guard(i))))
-            DBUG_RETURN(RES_ERROR);
+            DBUG_RETURN(true);
           if (!(having_col_item= 
                   new Item_func_trig_cond(having_col_item, get_cond_guard(i))))
-            DBUG_RETURN(RES_ERROR);
+            DBUG_RETURN(true);
         }
-        having_item= and_items(having_item, having_col_item);
+        *having_item= and_items(*having_item, having_col_item);
       }
-      where_item= and_items(where_item, item);
-    }
-    /*
-      AND can't be changed during fix_fields()
-      we can assign select_lex->where here, and pass 0 as last
-      argument (reference) to fix_fields()
-    */
-    select_lex->where= join->conds= and_items(join->conds, where_item);
-    select_lex->where->top_level_item();
-    if (join->conds->fix_fields(thd, 0))
-      DBUG_RETURN(RES_ERROR);
-  }
-  if (having_item)
-  {
-    bool res;
-    select_lex->having= join->having= and_items(join->having, having_item);
-    if (having_item == select_lex->having)
-      having_item->name= (char*)in_having_cond;
-    select_lex->having->top_level_item();
-    /*
-      AND can't be changed during fix_fields()
-      we can assign select_lex->having here, and pass 0 as last
-      argument (reference) to fix_fields()
-    */
-    select_lex->having_fix_field= 1;
-    res= join->having->fix_fields(thd, 0);
-    select_lex->having_fix_field= 0;
-    if (res)
-    {
-      DBUG_RETURN(RES_ERROR);
+      *where_item= and_items(*where_item, item);
     }
   }
 
-  DBUG_RETURN(RES_OK);
+  if (*where_item)
+  {
+    if (!(*where_item)->fixed && (*where_item)->fix_fields(thd, 0))
+      DBUG_RETURN(true);
+    (*where_item)->top_level_item();
+  }
+
+  if (*having_item)
+  {
+    if (!join_having)
+      (*having_item)->name= (char*) in_having_cond;
+    if (fix_having(*having_item, select_lex))
+      DBUG_RETURN(true);
+    (*having_item)->top_level_item();
+  }
+
+  DBUG_RETURN(false);
 }
 
 
-Item_subselect::trans_res
+bool
 Item_in_subselect::select_transformer(JOIN *join)
 {
-  return select_in_like_transformer(join, &eq_creator);
+  return select_in_like_transformer(join);
 }
 
 
 /**
-  Prepare IN/ALL/ANY/SOME subquery transformation and call appropriate
-  transformation function.
+  Create the predicates needed to transform an IN/ALL/ANY subselect into a
+  correlated EXISTS via predicate injection.
 
-    To decide which transformation procedure (scalar or row) applicable here
-    we have to call fix_fields() for left expression to be able to call
-    cols() method on it. Also this method make arena management for
-    underlying transformation methods.
+  @param join_arg  Join object of the subquery.
 
-  @param join    JOIN object of transforming subquery
-  @param func    creator of condition function of subquery
-
-  @retval
-    RES_OK      OK
-  @retval
-    RES_REDUCE  OK, and current subquery was reduced during
-    transformation
-  @retval
-    RES_ERROR   Error
+  @retval FALSE  ok
+  @retval TRUE   error
 */
 
-Item_subselect::trans_res
-Item_in_subselect::select_in_like_transformer(JOIN *join, Comp_creator *func)
+bool Item_in_subselect::create_in_to_exists_cond(JOIN *join_arg)
+{
+  bool res;
+
+  DBUG_ASSERT(engine->engine_type() == subselect_engine::SINGLE_SELECT_ENGINE ||
+              engine->engine_type() == subselect_engine::UNION_ENGINE);
+  /*
+    TODO: the call to init_cond_guards allocates and initializes an
+    array of booleans that may not be used later because we may choose
+    materialization.
+    The two calls below to create_XYZ_cond depend on this boolean array.
+    If the dependency is removed, the call can be moved to a later phase.
+  */
+  init_cond_guards();
+  /*
+    The IN=>EXISTS transformation makes non-correlated subqueries correlated.
+  */
+  join_arg->select_lex->uncacheable|= UNCACHEABLE_DEPENDENT;
+  if (left_expr->cols() == 1)
+    res= create_single_in_to_exists_cond(join_arg,
+                                         &(join_arg->in_to_exists_where),
+                                         &(join_arg->in_to_exists_having));
+  else
+    res= create_row_in_to_exists_cond(join_arg,
+                                      &(join_arg->in_to_exists_where),
+                                      &(join_arg->in_to_exists_having));
+  return (res);
+}
+
+
+/**
+  Transform an IN/ALL/ANY subselect into a correlated EXISTS via injecting
+  correlated in-to-exists predicates.
+
+  @param join_arg  Join object of the subquery.
+
+  @retval FALSE  ok
+  @retval TRUE   error
+*/
+
+bool Item_in_subselect::inject_in_to_exists_cond(JOIN *join_arg)
+{
+  SELECT_LEX *select_lex= join_arg->select_lex;
+  Item *where_item= join_arg->in_to_exists_where;
+  Item *having_item= join_arg->in_to_exists_having;
+
+  DBUG_ENTER("Item_in_subselect::inject_in_to_exists_cond");
+
+  if (where_item)
+  {
+    List<Item> *and_args= NULL;
+    /*
+      If the top-level Item of the WHERE clause is an AND, detach the multiple
+      equality list that was attached to the end of the AND argument list by
+      build_equal_items_for_cond(). The multiple equalities must be detached
+      because fix_fields merges lower level AND arguments into the upper AND.
+      As a result, the arguments from lower-level ANDs are concatenated after
+      the multiple equalities. When the multiple equality list is treated as
+      such, it turns out that it contains non-Item_equal object which is wrong.
+    */
+    if (join_arg->conds && join_arg->conds->type() == Item::COND_ITEM &&
+        ((Item_cond*) join_arg->conds)->functype() == Item_func::COND_AND_FUNC)
+    {
+      and_args= ((Item_cond*) join_arg->conds)->argument_list();
+      if (join_arg->cond_equal)
+        and_args->disjoin((List<Item> *) &join_arg->cond_equal->current_level);
+    }
+
+    where_item= and_items(join_arg->conds, where_item);
+    if (!where_item->fixed && where_item->fix_fields(thd, 0))
+      DBUG_RETURN(true);
+    // TIMOUR TODO: call optimize_cond() for the new where clause
+    thd->change_item_tree(&select_lex->where, where_item);
+    select_lex->where->top_level_item();
+    join_arg->conds= select_lex->where;
+
+    /* Attach back the list of multiple equalities to the new top-level AND. */
+    if (and_args && join_arg->cond_equal)
+    {
+      /* The argument list of the top-level AND may change after fix fields. */
+      and_args= ((Item_cond*) join_arg->conds)->argument_list();
+      and_args->concat((List<Item> *) &join_arg->cond_equal->current_level);
+    }
+  }
+
+  if (having_item)
+  {
+    Item* join_having= join_arg->having ? join_arg->having:join_arg->tmp_having;
+    having_item= and_items(join_having, having_item);
+    if (fix_having(having_item, select_lex))
+      DBUG_RETURN(true);
+    // TIMOUR TODO: call optimize_cond() for the new having clause
+    thd->change_item_tree(&select_lex->having, having_item);
+    select_lex->having->top_level_item();
+    join_arg->having= select_lex->having;
+  }
+
+  DBUG_RETURN(false);
+}
+
+
+/**
+  Prepare IN/ALL/ANY/SOME subquery transformation and call the appropriate
+  transformation function.
+
+  @param join    JOIN object of transforming subquery
+
+  @notes
+  To decide which transformation procedure (scalar or row) applicable here
+  we have to call fix_fields() for the left expression to be able to call
+  cols() method on it. Also this method makes arena management for
+  underlying transformation methods.
+
+  @retval  false  OK
+  @retval  true   Error
+*/
+
+bool
+Item_in_subselect::select_in_like_transformer(JOIN *join)
 {
   Query_arena *arena, backup;
   SELECT_LEX *current= thd->lex->current_select;
   const char *save_where= thd->where;
-  Item_subselect::trans_res res= RES_ERROR;
+  bool trans_res= true;
   bool result;
 
   DBUG_ENTER("Item_in_subselect::select_in_like_transformer");
 
+  /*
+    IN/SOME/ALL/ANY subqueries aren't support LIMIT clause. Without it
+    ORDER BY clause becomes meaningless thus we drop it here.
+  */
+  for (SELECT_LEX *sl= current->master_unit()->first_select();
+       sl; sl= sl->next_select())
   {
-    /*
-      IN/SOME/ALL/ANY subqueries aren't support LIMIT clause. Without it
-      ORDER BY clause becomes meaningless thus we drop it here.
-    */
-    SELECT_LEX *sl= current->master_unit()->first_select();
-    for (; sl; sl= sl->next_select())
+    if (sl->join)
     {
-      if (sl->join)
-        sl->join->order= 0;
+      sl->join->order= 0;
+      sl->join->skip_sort_order= 1;
     }
   }
 
   if (changed)
-    DBUG_RETURN(RES_OK);
+    DBUG_RETURN(false);
 
   thd->where= "IN/ALL/ANY subquery";
 
@@ -2078,14 +2185,6 @@ Item_in_subselect::select_in_like_transformer(JOIN *join, Comp_creator *func)
   if (result)
     goto err;
 
-  /*
-    If we didn't choose an execution method up to this point, we choose
-    the IN=>EXISTS transformation.
-  */
-  if (exec_method == NOT_TRANSFORMED)
-    exec_method= IN_TO_EXISTS;
-  arena= thd->activate_stmt_arena_if_needed(&backup);
-
   /*
     Both transformers call fix_fields() only for Items created inside them,
     and all that items do not make permanent changes in current item arena
@@ -2093,8 +2192,9 @@ Item_in_subselect::select_in_like_transformer(JOIN *join, Comp_creator *func)
     of Item, we have to call fix_fields() for it only with original arena to
     avoid memory leack)
   */
+  arena= thd->activate_stmt_arena_if_needed(&backup);
   if (left_expr->cols() == 1)
-    res= single_value_transformer(join, func);
+    trans_res= single_value_transformer(join);
   else
   {
     /* we do not support row operation for ALL/ANY/SOME */
@@ -2103,21 +2203,21 @@ Item_in_subselect::select_in_like_transformer(JOIN *join, Comp_creator *func)
       if (arena)
         thd->restore_active_arena(arena, &backup);
       my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
-      DBUG_RETURN(RES_ERROR);
+      DBUG_RETURN(true);
     }
-    res= row_value_transformer(join);
+    trans_res= row_value_transformer(join);
   }
   if (arena)
     thd->restore_active_arena(arena, &backup);
 err:
   thd->where= save_where;
-  DBUG_RETURN(res);
+  DBUG_RETURN(trans_res);
 }
 
 
 void Item_in_subselect::print(String *str, enum_query_type query_type)
 {
-  if (exec_method == IN_TO_EXISTS)
+  if (in_strategy & SUBS_IN_TO_EXISTS)
     str->append(STRING_WITH_LEN("<exists>"));
   else
   {
@@ -2133,7 +2233,7 @@ bool Item_in_subselect::fix_fields(THD *thd_arg, Item **ref)
   uint outer_cols_num;
   List<Item> *inner_cols;
 
-  if (exec_method == SEMI_JOIN)
+  if (in_strategy & SUBS_SEMI_JOIN)
     return !( (*ref)= new Item_int(1));
 
   /*
@@ -2206,99 +2306,47 @@ void Item_in_subselect::update_used_tables()
   used_tables_cache |= left_expr->used_tables();
 }
 
+
 /**
-  Try to create an engine to compute the subselect via materialization,
-  and if this fails, revert to execution via the IN=>EXISTS transformation.
+  Try to create and initialize an engine to compute a subselect via
+  materialization.
 
   @details
-    The purpose of this method is to hide the implementation details
-    of this Item's execution. The method creates a new engine for
-    materialized execution, and initializes the engine.
-
-    If this initialization fails
-    - either because it wasn't possible to create the needed temporary table
-      and its index,
-    - or because of a memory allocation error,
-    then we revert back to execution via the IN=>EXISTS tranformation.
-
-    The initialization of the new engine is divided in two parts - a permanent
-    one that lives across prepared statements, and one that is repeated for each
-    execution.
+  The method creates a new engine for materialized execution, and initializes
+  the engine. The initialization may fail
+  - either because it wasn't possible to create the needed temporary table
+    and its index,
+  - or because of a memory allocation error,
 
   @returns
     @retval TRUE  memory allocation error occurred
     @retval FALSE an execution method was chosen successfully
 */
 
-bool Item_in_subselect::setup_engine()
+bool Item_in_subselect::setup_mat_engine()
 {
-  subselect_hash_sj_engine *new_engine= NULL;
-  bool res= FALSE;
+  subselect_hash_sj_engine       *mat_engine= NULL;
+  subselect_single_select_engine *select_engine;
 
-  DBUG_ENTER("Item_in_subselect::setup_engine");
+  DBUG_ENTER("Item_in_subselect::setup_mat_engine");
 
-  if (engine->engine_type() == subselect_engine::SINGLE_SELECT_ENGINE)
-  {
-    /* Create/initialize objects in permanent memory. */
-    subselect_single_select_engine *old_engine;
-    Query_arena *arena= thd->stmt_arena, backup;
+  /*
+    The select_engine (that executes transformed IN=>EXISTS subselects) is
+    pre-created at parse time, and is stored in statment memory (preserved
+    across PS executions).
+  */
+  DBUG_ASSERT(engine->engine_type() == subselect_engine::SINGLE_SELECT_ENGINE);
+  select_engine= (subselect_single_select_engine*) engine;
 
-    old_engine= (subselect_single_select_engine*) engine;
+  /* Create/initialize execution objects. */
+  if (!(mat_engine= new subselect_hash_sj_engine(thd, this, select_engine)))
+    DBUG_RETURN(TRUE);
 
-    if (arena->is_conventional())
-      arena= 0;
-    else
-      thd->set_n_backup_active_arena(arena, &backup);
+  if (mat_engine->init(&select_engine->join->fields_list))
+    DBUG_RETURN(TRUE);
 
-    if (!(new_engine= new subselect_hash_sj_engine(thd, this,
-                                                   old_engine)) ||
-        new_engine->init_permanent(unit->get_unit_column_types()))
-    {
-      Item_subselect::trans_res trans_res;
-      /*
-        If for some reason we cannot use materialization for this IN predicate,
-        delete all materialization-related objects, and apply the IN=>EXISTS
-        transformation.
-      */
-      delete new_engine;
-      new_engine= NULL;
-      exec_method= NOT_TRANSFORMED;
-      if (left_expr->cols() == 1)
-        trans_res= single_value_in_to_exists_transformer(old_engine->join,
-                                                         &eq_creator);
-      else
-        trans_res= row_value_in_to_exists_transformer(old_engine->join);
-      res= (trans_res != Item_subselect::RES_OK);
-    }
-    if (new_engine)
-      engine= new_engine;
-
-    if (arena)
-      thd->restore_active_arena(arena, &backup);
-  }
-  else
-  {
-    DBUG_ASSERT(engine->engine_type() == subselect_engine::HASH_SJ_ENGINE);
-    new_engine= (subselect_hash_sj_engine*) engine;
-  }
-
-  /* Initilizations done in runtime memory, repeated for each execution. */
-  if (new_engine)
-  {
-    /*
-      Reset the LIMIT 1 set in Item_exists_subselect::fix_length_and_dec.
-      TODO:
-      Currently we set the subquery LIMIT to infinity, and this is correct
-      because we forbid at parse time LIMIT inside IN subqueries (see
-      Item_in_subselect::test_limit). However, once we allow this, here
-      we should set the correct limit if given in the query.
-    */
-    unit->global_parameters->select_limit= NULL;
-    if ((res= new_engine->init_runtime()))
-      DBUG_RETURN(res);
-  }
-
-  DBUG_RETURN(res);
+  engine= mat_engine;
+  DBUG_RETURN(FALSE);
 }
 
 
@@ -2341,39 +2389,34 @@ bool Item_in_subselect::init_left_expr_cache()
 }
 
 
-/*
-  Callback to test if an IN predicate is expensive.
-
-  @details
-    IN predicates are considered expensive only if they will be executed via
-    materialization. The return value affects the behavior of
-    make_cond_for_table() in such a way that it is unchanged when we use
-    the IN=>EXISTS transformation to compute IN.
-
-  @retval TRUE  if the predicate is expensive
-  @retval FALSE otherwise
-*/
-
-bool Item_in_subselect::is_expensive_processor(uchar *arg)
+bool Item_in_subselect::init_cond_guards()
 {
-  return exec_method == MATERIALIZATION;
+  uint cols_num= left_expr->cols();
+  if (!abort_on_null && left_expr->maybe_null && !pushed_cond_guards)
+  {
+    if (!(pushed_cond_guards= (bool*)thd->alloc(sizeof(bool) * cols_num)))
+        return TRUE;
+    for (uint i= 0; i < cols_num; i++)
+      pushed_cond_guards[i]= TRUE;
+  }
+  return FALSE;
 }
 
 
-Item_subselect::trans_res
+bool
 Item_allany_subselect::select_transformer(JOIN *join)
 {
   DBUG_ENTER("Item_allany_subselect::select_transformer");
-  exec_method= IN_TO_EXISTS;
+  in_strategy= SUBS_IN_TO_EXISTS;
   if (upper_item)
     upper_item->show= 1;
-  DBUG_RETURN(select_in_like_transformer(join, func));
+  DBUG_RETURN(select_in_like_transformer(join));
 }
 
 
 void Item_allany_subselect::print(String *str, enum_query_type query_type)
 {
-  if (exec_method == IN_TO_EXISTS)
+  if (in_strategy & SUBS_IN_TO_EXISTS)
     str->append(STRING_WITH_LEN("<exists>"));
   else
   {
@@ -3809,13 +3852,14 @@ bitmap_init_memroot(MY_BITMAP *map, uint n_bits, MEM_ROOT *mem_root)
   @retval FALSE otherwise
 */
 
-bool subselect_hash_sj_engine::init_permanent(List<Item> *tmp_columns)
+bool subselect_hash_sj_engine::init(List<Item> *tmp_columns)
 {
+  select_union *result_sink;
   /* Options to create_tmp_table. */
   ulonglong tmp_create_options= thd->options | TMP_TABLE_ALL_COLUMNS;
                              /* | TMP_TABLE_FORCE_MYISAM; TIMOUR: force MYISAM */
 
-  DBUG_ENTER("subselect_hash_sj_engine::init_permanent");
+  DBUG_ENTER("subselect_hash_sj_engine::init");
 
   if (bitmap_init_memroot(&non_null_key_parts, tmp_columns->elements,
                             thd->mem_root) ||
@@ -3844,15 +3888,16 @@ bool subselect_hash_sj_engine::init_permanent(List<Item> *tmp_columns)
     DBUG_RETURN(TRUE);
   }
 */
-  if (!(result= new select_materialize_with_stats))
+  if (!(result_sink= new select_materialize_with_stats))
+    DBUG_RETURN(TRUE);
+  result_sink->get_tmp_table_param()->materialized_subquery= true;
+  if (result_sink->create_result_table(thd, tmp_columns, TRUE,
+                                       tmp_create_options,
+                                       "materialized subselect", TRUE))
     DBUG_RETURN(TRUE);
 
-  if (((select_union*) result)->create_result_table(
-                         thd, tmp_columns, TRUE, tmp_create_options,
-                         "materialized subselect", TRUE))
-    DBUG_RETURN(TRUE);
-
-  tmp_table= ((select_union*) result)->table;
+  tmp_table= result_sink->table;
+  result= result_sink;
 
   /*
     If the subquery has blobs, or the total key lenght is bigger than
@@ -3889,6 +3934,17 @@ bool subselect_hash_sj_engine::init_permanent(List<Item> *tmp_columns)
       !(lookup_engine= make_unique_engine()))
     DBUG_RETURN(TRUE);
 
+  /*
+    Repeat name resolution for 'cond' since cond is not part of any
+    clause of the query, and it is not 'fixed' during JOIN::prepare.
+  */
+  if (semi_join_conds && !semi_join_conds->fixed &&
+      semi_join_conds->fix_fields(thd, (Item**)&semi_join_conds))
+    DBUG_RETURN(TRUE);
+  /* Let our engine reuse this query plan for materialization. */
+  materialize_join= materialize_engine->join;
+  materialize_join->change_result(result);
+
   DBUG_RETURN(FALSE);
 }
 
@@ -4001,35 +4057,6 @@ subselect_hash_sj_engine::make_unique_engine()
 }
 
 
-/**
-  Initialize members of the engine that need to be re-initilized at each
-  execution.
-
-  @retval TRUE  if a memory allocation error occurred
-  @retval FALSE if success
-*/
-
-bool subselect_hash_sj_engine::init_runtime()
-{
-  /*
-    Create and optimize the JOIN that will be used to materialize
-    the subquery if not yet created.
-  */
-  materialize_engine->prepare();
-  /*
-    Repeat name resolution for 'cond' since cond is not part of any
-    clause of the query, and it is not 'fixed' during JOIN::prepare.
-  */
-  if (semi_join_conds && !semi_join_conds->fixed &&
-      semi_join_conds->fix_fields(thd, (Item**)&semi_join_conds))
-    return TRUE;
-  /* Let our engine reuse this query plan for materialization. */
-  materialize_join= materialize_engine->join;
-  materialize_join->change_result(result);
-  return FALSE;
-}
-
-
 subselect_hash_sj_engine::~subselect_hash_sj_engine()
 {
   delete lookup_engine;
@@ -4039,6 +4066,16 @@ subselect_hash_sj_engine::~subselect_hash_sj_engine()
 }
 
 
+int subselect_hash_sj_engine::prepare()
+{
+  /*
+    Create and optimize the JOIN that will be used to materialize
+    the subquery if not yet created.
+  */
+  return materialize_engine->prepare();
+}
+
+
 /**
   Cleanup performed after each PS execution.
 
@@ -4056,6 +4093,12 @@ void subselect_hash_sj_engine::cleanup()
   count_null_only_columns= 0;
   strategy= UNDEFINED;
   materialize_engine->cleanup();
+  /*
+    Restore the original Item_in_subselect engine. This engine is created once
+    at parse time and stored across executions, while all other materialization
+    related engines are created and chosen for each execution.
+  */
+  ((Item_in_subselect *) item)->engine= materialize_engine;
   if (lookup_engine_type == TABLE_SCAN_ENGINE ||
       lookup_engine_type == ROWID_MERGE_ENGINE)
   {
@@ -4072,6 +4115,9 @@ void subselect_hash_sj_engine::cleanup()
   DBUG_ASSERT(lookup_engine->engine_type() == UNIQUESUBQUERY_ENGINE);
   lookup_engine->cleanup();
   result->cleanup(); /* Resets the temp table as well. */
+  DBUG_ASSERT(tmp_table);
+  free_tmp_table(thd, tmp_table);
+  tmp_table= NULL;
 }
 
 
@@ -4100,9 +4146,8 @@ int subselect_hash_sj_engine::exec()
     the subquery predicate.
   */
   thd->lex->current_select= materialize_engine->select_lex;
-  if ((res= materialize_join->optimize()))
-    goto err; /* purecov: inspected */
-  DBUG_ASSERT(!is_materialized); /* We should materialize only once. */
+  /* The subquery should be optimized, and materialized only once. */
+  DBUG_ASSERT(materialize_join->optimized && !is_materialized);
   materialize_join->exec();
   if ((res= test(materialize_join->error || thd->is_fatal_error)))
     goto err;
@@ -4126,11 +4171,10 @@ int subselect_hash_sj_engine::exec()
   tmp_table->file->info(HA_STATUS_VARIABLE);
   if (!tmp_table->file->stats.records)
   {
-    item_in->value= FALSE;
     /* The value of IN will not change during this execution. */
-    item_in->is_constant= TRUE;
+    item_in->reset();
+    item_in->make_const();
     item_in->set_first_execution();
-    /* TIMOUR: check if we need this: item_in->null_value= FALSE; */
     DBUG_RETURN(FALSE);
   }
 
diff --git a/sql/item_subselect.h b/sql/item_subselect.h
index 3b43d75f43f..740daeecf13 100644
--- a/sql/item_subselect.h
+++ b/sql/item_subselect.h
@@ -71,6 +71,13 @@ protected:
   
   bool inside_first_fix_fields;
   bool done_first_fix_fields;
+  /*
+    Set to TRUE if at optimization or execution time we determine that this
+    item's value is a constant. We need this member because it is not possible
+    to substitute 'this' with a constant item.
+  */
+  bool forced_const;
+
 public:
   /* A reference from inside subquery predicate to somewhere outside of it */
   class Ref_to_outside : public Sql_alloc
@@ -112,13 +119,18 @@ public:
   /* TRUE <=> The underlying SELECT is correlated w.r.t some ancestor select */
   bool is_correlated; 
 
-  enum trans_res {RES_OK, RES_REDUCE, RES_ERROR};
   enum subs_type {UNKNOWN_SUBS, SINGLEROW_SUBS,
 		  EXISTS_SUBS, IN_SUBS, ALL_SUBS, ANY_SUBS};
 
   Item_subselect();
 
   virtual subs_type substype() { return UNKNOWN_SUBS; }
+  bool is_in_predicate()
+  {
+    return (substype() == Item_subselect::IN_SUBS ||
+            substype() == Item_subselect::ALL_SUBS ||
+            substype() == Item_subselect::ANY_SUBS);
+  }
 
   /*
     We need this method, because some compilers do not allow 'this'
@@ -135,7 +147,7 @@ public:
     eliminated= FALSE;
     null_value= 1;
   }
-  virtual trans_res select_transformer(JOIN *join);
+  virtual bool select_transformer(JOIN *join);
   bool assigned() { return value_assigned; }
   void assigned(bool a) { value_assigned= a; }
   enum Type type() const;
@@ -149,12 +161,21 @@ public:
   void fix_after_pullout(st_select_lex *new_parent, Item **ref);
   void recalc_used_tables(st_select_lex *new_parent, bool after_pullout);
   virtual bool exec();
+  /*
+    If subquery optimization or execution determines that the subquery has
+    an empty result, mark the subquery predicate as a constant value.
+  */
+  void make_const()
+  { 
+    used_tables_cache= 0;
+    const_item_cache= 0;
+    forced_const= TRUE; 
+  }
   virtual void fix_length_and_dec();
   table_map used_tables() const;
   table_map not_null_tables() const { return 0; }
   bool const_item() const;
   inline table_map get_used_tables_cache() { return used_tables_cache; }
-  inline bool get_const_item_cache() { return const_item_cache; }
   Item *get_tmp_table_item(THD *thd);
   void update_used_tables();
   virtual void print(String *str, enum_query_type query_type);
@@ -172,6 +193,7 @@ public:
   */
   bool is_evaluated() const;
   bool is_uncacheable() const;
+  bool is_expensive() { return TRUE; }
 
   /*
     Used by max/min subquery to initialize value presence registration
@@ -181,12 +203,23 @@ public:
   enum_parsing_place place() { return parsing_place; }
   bool walk(Item_processor processor, bool walk_subquery, uchar *arg);
   bool mark_as_eliminated_processor(uchar *arg);
+  bool eliminate_subselect_processor(uchar *arg);
+  bool set_fake_select_as_master_processor(uchar *arg);
   bool enumerate_field_refs_processor(uchar *arg);
   bool check_vcol_func_processor(uchar *int_arg) 
   {
     return trace_unsupported_by_check_vcol_func_processor("subselect");
   }
+  /**
+    Callback to test if an IN predicate is expensive.
 
+    @notes
+    The return value affects the behavior of make_cond_for_table().
+
+    @retval TRUE  if the predicate is expensive
+    @retval FALSE otherwise
+  */
+  bool is_expensive_processor(uchar *arg) { return TRUE; }
   /**
     Get the SELECT_LEX structure associated with this Item.
     @return the SELECT_LEX structure associated with this Item
@@ -223,7 +256,7 @@ public:
   subs_type substype() { return SINGLEROW_SUBS; }
 
   void reset();
-  trans_res select_transformer(JOIN *join);
+  bool select_transformer(JOIN *join);
   void store(uint i, Item* item);
   double val_real();
   longlong val_int ();
@@ -312,6 +345,18 @@ public:
 };
 
 
+/*
+  Possible methods to execute an IN predicate. These are set by the optimizer
+  based on user-set optimizer switches, semantic analysis and cost comparison.
+*/
+#define SUBS_NOT_TRANSFORMED 0 /* No execution method was chosen for this IN. */
+#define SUBS_SEMI_JOIN 1       /* IN was converted to semi-join. */
+#define SUBS_IN_TO_EXISTS 2    /* IN was converted to correlated EXISTS. */
+#define SUBS_MATERIALIZATION 4 /* Execute IN via subquery materialization. */
+/* Partial matching substrategies of MATERIALIZATION. */
+#define SUBS_PARTIAL_MATCH_ROWID_MERGE 8
+#define SUBS_PARTIAL_MATCH_TABLE_SCAN 16
+
 /**
   Representation of IN subquery predicates of the form
   "left_expr IN (SELECT ...)".
@@ -329,8 +374,6 @@ public:
 
 class Item_in_subselect :public Item_exists_subselect
 {
-public:
-  Item *left_expr;
 protected:
   /*
     Cache of the left operand of the subquery predicate. Allocated in the
@@ -338,12 +381,6 @@ protected:
   */
   List<Cached_item> *left_expr_cache;
   bool first_execution;
-  /*
-    Set to TRUE if at query execution time we determine that this item's
-    value is a constant during this execution. We need this member because
-    it is not possible to substitute 'this' with a constant item.
-  */
-  bool is_constant;
 
   /*
     expr & optimizer used in subselect rewriting to store Item for
@@ -353,10 +390,24 @@ protected:
   Item_in_optimizer *optimizer;
   bool was_null;
   bool abort_on_null;
-public:
   /* Used to trigger on/off conditions that were pushed down to subselect */
   bool *pushed_cond_guards;
-  
+  Comp_creator *func;
+
+protected:
+  bool init_cond_guards();
+  bool select_in_like_transformer(JOIN *join);
+  bool single_value_transformer(JOIN *join);
+  bool row_value_transformer(JOIN * join);
+  bool fix_having(Item *having, st_select_lex *select_lex);
+  bool create_single_in_to_exists_cond(JOIN * join,
+                                       Item **where_item,
+                                       Item **having_item);
+  bool create_row_in_to_exists_cond(JOIN * join,
+                                    Item **where_item,
+                                    Item **having_item);
+public:
+  Item *left_expr;
   /* Priority of this predicate in the convert-to-semi-join-nest process. */
   int sj_convert_priority;
   /*
@@ -387,14 +438,8 @@ public:
   */
   bool sjm_scan_allowed;
 
-  /* The method chosen to execute the IN predicate.  */
-  enum enum_exec_method {
-    NOT_TRANSFORMED, /* No execution method was chosen for this IN. */
-    SEMI_JOIN,   /* IN was converted to semi-join nest and should be removed. */
-    IN_TO_EXISTS, /* IN was converted to correlated EXISTS. */
-    MATERIALIZATION /* IN will be executed via subquery materialization. */
-  };
-  enum_exec_method exec_method;
+  /* A bitmap of possible execution strategies for an IN predicate. */
+  uchar in_strategy;
 
   bool *get_cond_guard(int i)
   {
@@ -412,9 +457,10 @@ public:
   Item_in_subselect(Item * left_expr, st_select_lex *select_lex);
   Item_in_subselect()
     :Item_exists_subselect(), left_expr_cache(0), first_execution(TRUE),
-    is_constant(FALSE), optimizer(0), abort_on_null(0),
-    pushed_cond_guards(NULL), exec_method(NOT_TRANSFORMED), upper_item(0)
-  {}
+    optimizer(0), abort_on_null(0),
+    pushed_cond_guards(NULL), func(NULL), in_strategy(0),
+    upper_item(0)
+    {}
   void cleanup();
   subs_type substype() { return IN_SUBS; }
   void reset() 
@@ -424,13 +470,10 @@ public:
     null_value= 0;
     was_null= 0;
   }
-  trans_res select_transformer(JOIN *join);
-  trans_res select_in_like_transformer(JOIN *join, Comp_creator *func);
-  trans_res single_value_transformer(JOIN *join, Comp_creator *func);
-  trans_res row_value_transformer(JOIN * join);
-  trans_res single_value_in_to_exists_transformer(JOIN * join,
-                                                  Comp_creator *func);
-  trans_res row_value_in_to_exists_transformer(JOIN * join);
+  bool select_transformer(JOIN *join);
+  bool create_in_to_exists_cond(JOIN *join_arg);
+  bool inject_in_to_exists_cond(JOIN *join_arg);
+
   virtual bool exec();
   longlong val_int();
   double val_real();
@@ -445,11 +488,10 @@ public:
   bool fix_fields(THD *thd, Item **ref);
   void fix_after_pullout(st_select_lex *new_parent, Item **ref);
   void update_used_tables();
-  bool setup_engine();
+  bool setup_mat_engine();
   bool init_left_expr_cache();
   /* Inform 'this' that it was computed, and contains a valid result. */
   void set_first_execution() { if (first_execution) first_execution= FALSE; }
-  bool is_expensive_processor(uchar *arg);
   bool expr_cache_is_needed(THD *thd);
   
   /* 
@@ -471,7 +513,6 @@ class Item_allany_subselect :public Item_in_subselect
 {
 public:
   chooser_compare_func_creator func_creator;
-  Comp_creator *func;
   bool all;
 
   Item_allany_subselect(Item * left_expr, chooser_compare_func_creator fc,
@@ -479,7 +520,8 @@ public:
 
   // only ALL subquery has upper not
   subs_type substype() { return all?ALL_SUBS:ANY_SUBS; }
-  trans_res select_transformer(JOIN *join);
+  bool select_transformer(JOIN *join);
+  void create_comp_func(bool invert) { func= func_creator(invert); }
   virtual void print(String *str, enum_query_type query_type);
 };
 
@@ -817,10 +859,9 @@ public:
   {}
   ~subselect_hash_sj_engine();
 
-  bool init_permanent(List<Item> *tmp_columns);
-  bool init_runtime();
+  bool init(List<Item> *tmp_columns);
   void cleanup();
-  int prepare() { return 0; } /* Override virtual function in base class. */
+  int prepare();
   int exec();
   virtual void print(String *str, enum_query_type query_type);
   uint cols()
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 7de02d726fa..f937394613e 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -1053,9 +1053,10 @@ bool Item_sum_distinct::unique_walk_function(void *element)
 void Item_sum_distinct::clear()
 {
   DBUG_ENTER("Item_sum_distinct::clear");
-  DBUG_ASSERT(tree != 0);                        /* we always have a tree */
+  /* During EXPLAIN there is no tree because it is created during execution. */
+  if (tree != 0)
+    tree->reset();
   null_value= 1;
-  tree->reset();
   is_evaluated= FALSE;
   DBUG_VOID_RETURN;
 }
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index 912f33ac983..a0184a82f48 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -570,26 +570,32 @@ protected:
 #define OPTIMIZER_SWITCH_FIRSTMATCH 64
 #define OPTIMIZER_SWITCH_LOOSE_SCAN 128
 #define OPTIMIZER_SWITCH_MATERIALIZATION 256
-#define OPTIMIZER_SWITCH_SEMIJOIN 512
-#define OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE 1024
-#define OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN (1<<11)
-#define OPTIMIZER_SWITCH_SUBQUERY_CACHE (1<<12)
-#define OPTIMIZER_SWITCH_MRR_SORT_KEYS (1<<13)
-#define OPTIMIZER_SWITCH_OUTER_JOIN_WITH_CACHE (1<<14)
-#define OPTIMIZER_SWITCH_SEMIJOIN_WITH_CACHE (1<<15)
-#define OPTIMIZER_SWITCH_JOIN_CACHE_INCREMENTAL (1<<16)
-#define OPTIMIZER_SWITCH_JOIN_CACHE_HASHED (1<<17)
-#define OPTIMIZER_SWITCH_JOIN_CACHE_BKA (1<<18)
-#define OPTIMIZER_SWITCH_OPTIMIZE_JOIN_BUFFER_SIZE (1<<19)
+#define OPTIMIZER_SWITCH_IN_TO_EXISTS 512
+#define OPTIMIZER_SWITCH_SEMIJOIN 1024
+#define OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE  (1<<11)
+#define OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN (1<<12)
+#define OPTIMIZER_SWITCH_SUBQUERY_CACHE (1<<13)
+#define OPTIMIZER_SWITCH_MRR_SORT_KEYS (1<<14)
+#define OPTIMIZER_SWITCH_OUTER_JOIN_WITH_CACHE (1<<15)
+#define OPTIMIZER_SWITCH_SEMIJOIN_WITH_CACHE (1<<16)
+#define OPTIMIZER_SWITCH_JOIN_CACHE_INCREMENTAL (1<<17)
+#define OPTIMIZER_SWITCH_JOIN_CACHE_HASHED (1<<18)
+#define OPTIMIZER_SWITCH_JOIN_CACHE_BKA (1<<19)
+#define OPTIMIZER_SWITCH_OPTIMIZE_JOIN_BUFFER_SIZE (1<<20)
 #ifdef DBUG_OFF
-#  define OPTIMIZER_SWITCH_LAST (1<<20)
-#else
-#  define OPTIMIZER_SWITCH_TABLE_ELIMINATION (1<<20)
 #  define OPTIMIZER_SWITCH_LAST (1<<21)
+#else
+#  define OPTIMIZER_SWITCH_TABLE_ELIMINATION (1<<21)
+#  define OPTIMIZER_SWITCH_LAST (1<<22)
 #endif
 
 #ifdef DBUG_OFF 
 /* The following must be kept in sync with optimizer_switch_str in mysqld.cc */
+/*
+TODO: Materialization is off by default to mimic 5.1/5.2 behavior.
+Once cost based choice between materialization and in-to-exists should be
+enabled by default, add OPTIMIZER_SWITCH_MATERIALIZATION
+*/
 #  define OPTIMIZER_SWITCH_DEFAULT (OPTIMIZER_SWITCH_INDEX_MERGE | \
                                     OPTIMIZER_SWITCH_INDEX_MERGE_UNION | \
                                     OPTIMIZER_SWITCH_INDEX_MERGE_SORT_UNION | \
@@ -597,7 +603,7 @@ protected:
                                     OPTIMIZER_SWITCH_INDEX_COND_PUSHDOWN | \
                                     OPTIMIZER_SWITCH_FIRSTMATCH | \
                                     OPTIMIZER_SWITCH_LOOSE_SCAN | \
-                                    OPTIMIZER_SWITCH_MATERIALIZATION | \
+                                    OPTIMIZER_SWITCH_IN_TO_EXISTS | \
                                     OPTIMIZER_SWITCH_SEMIJOIN | \
                                     OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE|\
                                     OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN|\
@@ -617,7 +623,7 @@ protected:
                                     OPTIMIZER_SWITCH_TABLE_ELIMINATION | \
                                     OPTIMIZER_SWITCH_FIRSTMATCH | \
                                     OPTIMIZER_SWITCH_LOOSE_SCAN | \
-                                    OPTIMIZER_SWITCH_MATERIALIZATION | \
+                                    OPTIMIZER_SWITCH_IN_TO_EXISTS | \
                                     OPTIMIZER_SWITCH_SEMIJOIN | \
                                     OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE|\
                                     OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN|\
@@ -1630,6 +1636,7 @@ inline bool setup_fields_with_no_wrap(THD *thd, Item **ref_pointer_array,
 }
 int setup_conds(THD *thd, TABLE_LIST *tables, TABLE_LIST *leaves,
 		COND **conds);
+void wrap_ident(THD *thd, Item **conds);
 int setup_ftfuncs(SELECT_LEX* select);
 int init_ftfuncs(THD *thd, SELECT_LEX* select, bool no_order);
 void wait_for_condition(THD *thd, pthread_mutex_t *mutex,
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 68140ae1b5a..c30da7b03e5 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -335,7 +335,7 @@ static const char *optimizer_switch_names[]=
   "index_merge","index_merge_union","index_merge_sort_union",
   "index_merge_intersection","index_merge_sort_intersection",
   "index_condition_pushdown",
-  "firstmatch","loosescan","materialization", "semijoin",
+  "firstmatch","loosescan","materialization","in_to_exists","semijoin",
   "partial_match_rowid_merge",
   "partial_match_table_scan",
   "subquery_cache",
@@ -364,6 +364,7 @@ static const unsigned int optimizer_switch_names_len[]=
   sizeof("firstmatch") - 1,
   sizeof("loosescan") - 1,
   sizeof("materialization") - 1,
+  sizeof("in_to_exists") - 1,
   sizeof("semijoin") - 1,
   sizeof("partial_match_rowid_merge") - 1,
   sizeof("partial_match_table_scan") - 1,
@@ -470,7 +471,8 @@ static const char *optimizer_switch_str="index_merge=on,index_merge_union=on,"
                                         "index_condition_pushdown=on,"
                                         "firstmatch=on,"
                                         "loosescan=on,"
-                                        "materialization=on,"
+                                        "materialization=off,"
+                                        "in_to_exists=on,"
                                         "semijoin=on,"
                                         "partial_match_rowid_merge=on,"
                                         "partial_match_table_scan=on,"
@@ -7444,7 +7446,7 @@ each time the SQL thread starts.",
    "optimizer_switch=option=val[,option=val...], where option={index_merge, "
    "index_merge_union, index_merge_sort_union, index_merge_intersection, "
    "index_merge_sort_intersection, "
-   "index_condition_pushdown, firstmatch, loosescan, materialization, "
+   "index_condition_pushdown, firstmatch, loosescan, materialization, in_to_exists, "
    "semijoin, partial_match_rowid_merge, partial_match_table_scan, "
    "subquery_cache, outer_join_with_cache, semijoin_with_cache, "
    "join_cache_incremental, join_cache_hashed, join_cache_bka, "
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index a605b3f8fe1..5d524c3acd1 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -11104,7 +11104,7 @@ static bool get_constant_key_infix(KEY *index_info, SEL_ARG *index_range_tree,
                        uchar *key_infix, uint *key_infix_len,
                        KEY_PART_INFO **first_non_infix_part);
 static bool
-check_group_min_max_predicates(COND *cond, Item_field *min_max_arg_item,
+check_group_min_max_predicates(Item *cond, Item_field *min_max_arg_item,
                                Field::imagetype image_type);
 
 static void
@@ -11678,14 +11678,14 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree)
 */
 
 static bool
-check_group_min_max_predicates(COND *cond, Item_field *min_max_arg_item,
+check_group_min_max_predicates(Item *cond, Item_field *min_max_arg_item,
                                Field::imagetype image_type)
 {
   DBUG_ENTER("check_group_min_max_predicates");
   DBUG_ASSERT(cond && min_max_arg_item);
 
   cond= cond->real_item();
-  Item::Type cond_type= cond->type();
+  Item::Type cond_type= cond->real_type();
   if (cond_type == Item::COND_ITEM) /* 'AND' or 'OR' */
   {
     DBUG_PRINT("info", ("Analyzing: %s", ((Item_func*) cond)->func_name()));
@@ -11701,16 +11701,25 @@ check_group_min_max_predicates(COND *cond, Item_field *min_max_arg_item,
   }
 
   /*
-    TODO:
-    This is a very crude fix to handle sub-selects in the WHERE clause
-    (Item_subselect objects). With the test below we rule out from the
-    optimization all queries with subselects in the WHERE clause. What has to
-    be done, is that here we should analyze whether the subselect references
-    the MIN/MAX argument field, and disallow the optimization only if this is
-    so.
+    Disallow loose index scan if the MIN/MAX argument field is referenced by
+    a subquery in the WHERE clause.
   */
-  if (cond->real_type() == Item::SUBSELECT_ITEM)
-    DBUG_RETURN(FALSE);
+  if (cond_type == Item::SUBSELECT_ITEM)
+  {
+    Item_subselect *subs_cond= (Item_subselect*) cond;
+    if (subs_cond->is_correlated)
+    {
+      DBUG_ASSERT(subs_cond->depends_on.elements > 0);
+      List_iterator_fast<Item*> li(subs_cond->depends_on);
+      Item **dep;
+      while ((dep= li++))
+      {
+        if ((*dep)->eq(min_max_arg_item, FALSE))
+          DBUG_RETURN(FALSE);
+      }
+    }
+    DBUG_RETURN(TRUE);
+  }
 
   /*
     Condition of the form 'field' is equivalent to 'field <> 0' and thus
diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc
index e12412299c5..9469f35e21c 100644
--- a/sql/opt_subselect.cc
+++ b/sql/opt_subselect.cc
@@ -29,6 +29,10 @@ static TABLE_LIST *alloc_join_nest(THD *thd);
 static 
 void fix_list_after_tbl_changes(SELECT_LEX *new_parent, List<TABLE_LIST> *tlist);
 static uint get_tmp_table_rec_length(List<Item> &items);
+static double get_tmp_table_lookup_cost(THD *thd, double row_count,
+                                        uint row_size);
+static double get_tmp_table_write_cost(THD *thd, double row_count,
+                                       uint row_size);
 bool find_eq_ref_candidate(TABLE *table, table_map sj_inner_tables);
 static SJ_MATERIALIZATION_INFO *
 at_sjmat_pos(const JOIN *join, table_map remaining_tables, const JOIN_TAB *tab,
@@ -67,6 +71,7 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
 {
   THD *thd=join->thd;
   st_select_lex *select_lex= join->select_lex;
+  st_select_lex_unit* parent_unit= select_lex->master_unit();
   DBUG_ENTER("check_and_do_in_subquery_rewrites");
   /*
     If 
@@ -85,7 +90,7 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
   */
   Item_subselect *subselect;
   if (!(thd->lex->context_analysis_only & CONTEXT_ANALYSIS_ONLY_VIEW) && // (1)
-    (subselect= select_lex->master_unit()->item))      // (2)
+      (subselect= parent_unit->item))                                    // (2)
   {
     Item_in_subselect *in_subs= NULL;
     if (subselect->substype() == Item_subselect::IN_SUBS)
@@ -129,6 +134,15 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
       if (failure)
         DBUG_RETURN(-1); /* purecov: deadcode */
     }
+    if (select_lex == parent_unit->fake_select_lex)
+    {
+      /*
+        The join and its select_lex object represent the 'fake' select used
+        to compute the result of a UNION.
+      */
+      DBUG_RETURN(0);
+    }
+
     DBUG_PRINT("info", ("Checking if subq can be converted to semi-join"));
     /*
       Check if we're in subquery that is a candidate for flattening into a
@@ -154,8 +168,8 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
         !join->having && !select_lex->with_sum_func &&                // 4
         thd->thd_marker.emb_on_expr_nest &&                           // 5
         select_lex->outer_select()->join &&                           // 6
-        select_lex->master_unit()->first_select()->leaf_tables &&     // 7
-        in_subs->exec_method == Item_in_subselect::NOT_TRANSFORMED && // 8
+        parent_unit->first_select()->leaf_tables &&                   // 7
+        !in_subs->in_strategy &&                                      // 8
         select_lex->outer_select()->leaf_tables &&                    // 9
         !((join->select_options |                                     // 10
            select_lex->outer_select()->join->select_options)          // 10
@@ -175,63 +189,80 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
     else
     {
       DBUG_PRINT("info", ("Subquery can't be converted to semi-join"));
-      /*
-        Check if the subquery predicate can be executed via materialization.
-        The required conditions are:
-        1. Subquery predicate is an IN/=ANY subq predicate
-        2. Subquery is a single SELECT (not a UNION)
-        3. Subquery is not a table-less query. In this case there is no
-           point in materializing.
-          3A The upper query is not a table-less SELECT ... FROM DUAL. We
+      /* Test if the user has set a legal combination of optimizer switches. */
+      if (!optimizer_flag(thd, OPTIMIZER_SWITCH_IN_TO_EXISTS) &&
+          !optimizer_flag(thd, OPTIMIZER_SWITCH_MATERIALIZATION))
+        my_error(ER_ILLEGAL_SUBQUERY_OPTIMIZER_SWITCHES, MYF(0));
+
+      if (in_subs)
+      {
+        /* Subquery predicate is an IN/=ANY predicate. */
+        if (optimizer_flag(thd, OPTIMIZER_SWITCH_IN_TO_EXISTS))
+          in_subs->in_strategy|= SUBS_IN_TO_EXISTS;
+        if (optimizer_flag(thd, OPTIMIZER_SWITCH_MATERIALIZATION))
+          in_subs->in_strategy|= SUBS_MATERIALIZATION;
+
+        /*
+          Check if the subquery predicate can be executed via materialization.
+          The required conditions are:
+          1. Subquery is a single SELECT (not a UNION)
+          2. Subquery is not a table-less query. In this case there is no
+             point in materializing.
+          2A The upper query is not a table-less SELECT ... FROM DUAL. We
              can't do materialization for SELECT .. FROM DUAL because it
              does not call setup_subquery_materialization(). We could make 
              SELECT ... FROM DUAL call that function but that doesn't seem
              to be the case that is worth handling.
-        4. Either the subquery predicate is a top-level predicate, or at
-           least one partial match strategy is enabled. If no partial match
-           strategy is enabled, then materialization cannot be used for
-           non-top-level queries because it cannot handle NULLs correctly.
-        5. Subquery is non-correlated
-           TODO:
-           This is an overly restrictive condition. It can be extended to:
-           (Subquery is non-correlated ||
-            Subquery is correlated to any query outer to IN predicate ||
-            (Subquery is correlated to the immediate outer query &&
-             Subquery !contains {GROUP BY, ORDER BY [LIMIT],
-             aggregate functions}) && subquery predicate is not under "NOT IN"))
-        6. No execution method was already chosen (by a prepared statement).
+          3. Either the subquery predicate is a top-level predicate, or at
+             least one partial match strategy is enabled. If no partial match
+             strategy is enabled, then materialization cannot be used for
+             non-top-level queries because it cannot handle NULLs correctly.
+          4. Subquery is non-correlated
+             TODO:
+             This is an overly restrictive condition. It can be extended to:
+             (Subquery is non-correlated ||
+              Subquery is correlated to any query outer to IN predicate ||
+              (Subquery is correlated to the immediate outer query &&
+               Subquery !contains {GROUP BY, ORDER BY [LIMIT],
+               aggregate functions}) && subquery predicate is not under "NOT IN"))
 
-        (*) The subquery must be part of a SELECT statement. The current
-             condition also excludes multi-table update statements.
+          (*) The subquery must be part of a SELECT statement. The current
+               condition also excludes multi-table update statements.
+        */
+        if (!(in_subs->in_strategy & SUBS_MATERIALIZATION && 
+              !select_lex->is_part_of_union() &&                            // 1
+              parent_unit->first_select()->leaf_tables &&                   // 2
+              thd->lex->sql_command == SQLCOM_SELECT &&                     // *
+              select_lex->outer_select()->leaf_tables &&                    // 2A
+              subquery_types_allow_materialization(in_subs) &&
+              // psergey-todo: duplicated_subselect_card_check: where it's done?
+              (in_subs->is_top_level_item() ||                               //3
+               optimizer_flag(thd,
+                              OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE) || //3
+               optimizer_flag(thd,
+                              OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN)) && //3
+              !in_subs->is_correlated))                                      //4
+        {
+          /* Materialization is not possible based on syntactic properties. */
+          in_subs->in_strategy&= ~SUBS_MATERIALIZATION;
+        }
 
-        Determine whether we will perform subquery materialization before
-        calling the IN=>EXISTS transformation, so that we know whether to
-        perform the whole transformation or only that part of it which wraps
-        Item_in_subselect in an Item_in_optimizer.
+        if (!in_subs->in_strategy)
+        {
+          /*
+            If neither materialization is possible, nor the user chose
+            IN-TO-EXISTS, choose IN-TO-EXISTS as the only universal strategy.
+          */
+          in_subs->in_strategy|= SUBS_IN_TO_EXISTS;
+        }
+      }
+
+      /*
+        Transform each subquery predicate according to its overloaded
+        transformer.
       */
-      if (optimizer_flag(thd, OPTIMIZER_SWITCH_MATERIALIZATION)  && 
-          in_subs  &&                                                   // 1
-          !select_lex->is_part_of_union() &&                            // 2
-          select_lex->master_unit()->first_select()->leaf_tables &&     // 3
-          thd->lex->sql_command == SQLCOM_SELECT &&                     // *
-          select_lex->outer_select()->leaf_tables &&                    // 3A
-          subquery_types_allow_materialization(in_subs) &&
-          // psergey-todo: duplicated_subselect_card_check: where it's done?
-          (in_subs->is_top_level_item() ||
-           optimizer_flag(thd, OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE) ||
-           optimizer_flag(thd, OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN)) &&//4
-          !in_subs->is_correlated &&                                  // 5
-          in_subs->exec_method == Item_in_subselect::NOT_TRANSFORMED) // 6
-      {
-          in_subs->exec_method= Item_in_subselect::MATERIALIZATION;
-      }
-
-      Item_subselect::trans_res trans_res;
-      if ((trans_res= subselect->select_transformer(join)) !=
-          Item_subselect::RES_OK)
-      {
-        DBUG_RETURN((trans_res == Item_subselect::RES_ERROR));
-      }
+      if (subselect->select_transformer(join))
+        DBUG_RETURN(-11);
     }
   }
   DBUG_RETURN(0);
@@ -473,18 +504,17 @@ skip_conversion:
   for (; in_subq!= in_subq_end; in_subq++)
   {
     JOIN *child_join= (*in_subq)->unit->first_select()->join;
-    Item_subselect::trans_res res;
     (*in_subq)->changed= 0;
     (*in_subq)->fixed= 0;
 
     SELECT_LEX *save_select_lex= thd->lex->current_select;
     thd->lex->current_select= (*in_subq)->unit->first_select();
 
-    res= (*in_subq)->select_transformer(child_join);
+    bool res= (*in_subq)->select_transformer(child_join);
 
     thd->lex->current_select= save_select_lex;
 
-    if (res == Item_subselect::RES_ERROR)
+    if (res)
       DBUG_RETURN(TRUE);
 
     (*in_subq)->changed= 1;
@@ -509,6 +539,15 @@ skip_conversion:
                                      FALSE))
         DBUG_RETURN(TRUE);
     }
+    /*
+      Revert to the IN->EXISTS strategy in the rare case when the subquery could
+      not be flattened.
+      TODO: This is a limitation done for simplicity. Such subqueries could also
+      be executed via materialization. In order to determine this, we should
+      re-run the test for materialization that was done in
+      check_and_do_in_subquery_rewrites.
+    */
+    (*in_subq)->in_strategy= SUBS_IN_TO_EXISTS;
   }
 
   if (arena)
@@ -769,8 +808,7 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
   /* 3. Remove the original subquery predicate from the WHERE/ON */
 
   // The subqueries were replaced for Item_int(1) earlier
-  subq_pred->exec_method=
-    Item_in_subselect::SEMI_JOIN;         // for subsequent executions
+  subq_pred->in_strategy= SUBS_SEMI_JOIN;         // for subsequent executions
   /*TODO: also reset the 'with_subselect' there. */
 
   /* n. Adjust the parent_join->tables counter */
@@ -872,7 +910,14 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
   {
     /* Inject into the WHERE */
     parent_join->conds= and_items(parent_join->conds, sj_nest->sj_on_expr);
+    /*
+      fix_fields must update the properties (e.g. st_select_lex::cond_count of
+      the correct select_lex.
+    */
+    save_lex= thd->lex->current_select;
+    thd->lex->current_select=parent_join->select_lex;
     parent_join->conds->fix_fields(parent_join->thd, &parent_join->conds);
+    thd->lex->current_select=save_lex;
     parent_join->select_lex->where= parent_join->conds;
   }
 
@@ -1167,8 +1212,8 @@ bool optimize_semijoin_nests(JOIN *join, table_map all_table_map)
         sjm->tables= n_tables;
         sjm->is_used= FALSE;
         double subjoin_out_rows, subjoin_read_time;
-        get_partial_join_cost(join, n_tables,
-                              &subjoin_read_time, &subjoin_out_rows);
+        join->get_partial_join_cost(n_tables + join->const_tables,
+                                    &subjoin_read_time, &subjoin_out_rows);
 
         sjm->materialization_cost.convert_from_cost(subjoin_read_time);
         sjm->rows= subjoin_out_rows;
@@ -1216,17 +1261,16 @@ bool optimize_semijoin_nests(JOIN *join, table_map all_table_map)
           Calculate temporary table parameters and usage costs
         */
         uint rowlen= get_tmp_table_rec_length(right_expr_list);
-        double lookup_cost;
-        if (rowlen * subjoin_out_rows< join->thd->variables.max_heap_table_size)
-          lookup_cost= HEAP_TEMPTABLE_LOOKUP_COST;
-        else
-          lookup_cost= DISK_TEMPTABLE_LOOKUP_COST;
+        double lookup_cost= get_tmp_table_lookup_cost(join->thd,
+                                                      subjoin_out_rows, rowlen);
+        double write_cost= get_tmp_table_write_cost(join->thd,
+                                                    subjoin_out_rows, rowlen);
 
         /*
           Let materialization cost include the cost to write the data into the
           temporary table:
         */ 
-        sjm->materialization_cost.add_io(subjoin_out_rows, lookup_cost);
+        sjm->materialization_cost.add_io(subjoin_out_rows, write_cost);
         
         /*
           Set the cost to do a full scan of the temptable (will need this to 
@@ -1301,6 +1345,51 @@ static uint get_tmp_table_rec_length(List<Item> &items)
   return len;
 }
 
+
+/**
+  The cost of a lookup into a unique hash/btree index on a temporary table
+  with 'row_count' rows each of size 'row_size'.
+
+  @param thd  current query context
+  @param row_count  number of rows in the temp table
+  @param row_size   average size in bytes of the rows
+
+  @return  the cost of one lookup
+*/
+
+static double
+get_tmp_table_lookup_cost(THD *thd, double row_count, uint row_size)
+{
+  if (row_count * row_size > thd->variables.max_heap_table_size)
+    return (double) DISK_TEMPTABLE_LOOKUP_COST;
+  else
+    return (double) HEAP_TEMPTABLE_LOOKUP_COST;
+}
+
+/**
+  The cost of writing a row into a temporary table with 'row_count' unique
+  rows each of size 'row_size'.
+
+  @param thd  current query context
+  @param row_count  number of rows in the temp table
+  @param row_size   average size in bytes of the rows
+
+  @return  the cost of writing one row
+*/
+
+static double
+get_tmp_table_write_cost(THD *thd, double row_count, uint row_size)
+{
+  double lookup_cost= get_tmp_table_lookup_cost(thd, row_count, row_size);
+  /*
+    TODO:
+    This is an optimistic estimate. Add additional costs resulting from
+    actually writing the row to memory/disk and possible index reorganization.
+  */
+  return lookup_cost;
+}
+
+
 //psergey-todo: is the below a kind of table elimination??
 /*
   Check if table's KEYUSE elements have an eq_ref(outer_tables) candidate
@@ -1830,15 +1919,15 @@ void advance_sj_state(JOIN *join, table_map remaining_tables,
         - sj_inner_fanout*sj_outer_fanout  lookups.
 
       */
-      double one_lookup_cost;
-      if (sj_outer_fanout*temptable_rec_size > 
-          join->thd->variables.max_heap_table_size)
-        one_lookup_cost= DISK_TEMPTABLE_LOOKUP_COST;
-      else
-        one_lookup_cost= HEAP_TEMPTABLE_LOOKUP_COST;
+      double one_lookup_cost= get_tmp_table_lookup_cost(join->thd,
+                                                        sj_outer_fanout,
+                                                        temptable_rec_size);
+      double one_write_cost= get_tmp_table_write_cost(join->thd,
+                                                      sj_outer_fanout,
+                                                      temptable_rec_size);
 
       double write_cost= join->positions[first_tab].prefix_record_count* 
-                         sj_outer_fanout * one_lookup_cost;
+                         sj_outer_fanout * one_write_cost;
       double full_lookup_cost= join->positions[first_tab].prefix_record_count* 
                                sj_outer_fanout* sj_inner_fanout * 
                                one_lookup_cost;
@@ -3360,9 +3449,23 @@ int rewrite_to_index_subquery_engine(JOIN *join)
   JOIN_TAB* join_tab=join->join_tab;
   SELECT_LEX_UNIT *unit= join->unit;
   DBUG_ENTER("rewrite_to_index_subquery_engine");
+
   /*
     is this simple IN subquery?
   */
+  /* TODO: In order to use these more efficient subquery engines in more cases,
+     the following problems need to be solved:
+     - the code that removes GROUP BY (group_list), also adds an ORDER BY
+       (order), thus GROUP BY queries (almost?) never pass through this branch.
+       Solution: remove the test below '!join->order', because we remove the
+       ORDER clase for subqueries anyway.
+     - in order to set a more efficient engine, the optimizer needs to both
+       decide to remove GROUP BY, *and* select one of the JT_[EQ_]REF[_OR_NULL]
+       access methods, *and* loose scan should be more expensive or
+       inapliccable. When is that possible?
+     - Consider expanding the applicability of this rewrite for loose scan
+       for group by queries.
+  */
   if (!join->group_list && !join->order &&
       join->unit->item && 
       join->unit->item->substype() == Item_subselect::IN_SUBS &&
@@ -3503,3 +3606,349 @@ static void remove_subq_pushed_predicates(JOIN *join, Item **where)
 }
 
 
+/**
+  Optimize all subqueries of a query that have were flattened into a semijoin.
+
+  @details
+  Optimize all immediate children subqueries of a query.
+
+  This phase must be called after substitute_for_best_equal_field() because
+  that function may replace items with other items from a multiple equality,
+  and we need to reference the correct items in the index access method of the
+  IN predicate.
+
+  @return Operation status
+  @retval FALSE     success.
+  @retval TRUE      error occurred.
+*/
+
+bool JOIN::optimize_unflattened_subqueries()
+{
+  return select_lex->optimize_unflattened_subqueries();
+}
+
+
+/**
+  Choose an optimal strategy to execute an IN/ALL/ANY subquery predicate
+  based on cost.
+
+  @param join_tables  the set of tables joined in the subquery
+
+  @notes
+  The method chooses between the materialization and IN=>EXISTS rewrite
+  strategies for the execution of a non-flattened subquery IN predicate.
+  The cost-based decision is made as follows:
+
+  1. compute materialize_strategy_cost based on the unmodified subquery
+  2. reoptimize the subquery taking into account the IN-EXISTS predicates
+  3. compute in_exists_strategy_cost based on the reoptimized plan
+  4. compare and set the cheaper strategy
+     if (materialize_strategy_cost >= in_exists_strategy_cost)
+       in_strategy = MATERIALIZATION
+     else
+       in_strategy = IN_TO_EXISTS
+  5. if in_strategy = MATERIALIZATION and it is not possible to initialize it
+       revert to IN_TO_EXISTS
+  6. if (in_strategy == MATERIALIZATION)
+       revert the subquery plan to the original one before reoptimizing
+     else
+       inject the IN=>EXISTS predicates into the new EXISTS subquery plan
+
+  The implementation itself is a bit more complicated because it takes into
+  account two more factors:
+  - whether the user allowed both strategies through an optimizer_switch, and
+  - if materialization was the cheaper strategy, whether it can be executed
+    or not.
+
+  @retval FALSE     success.
+  @retval TRUE      error occurred.
+*/
+
+bool JOIN::choose_subquery_plan(table_map join_tables)
+{
+  Query_plan_state save_qep; /* The original QEP of the subquery. */
+  enum_reopt_result reopt_result= REOPT_NONE;
+  Item_in_subselect *in_subs;
+
+  if (select_lex->master_unit()->item &&
+      select_lex->master_unit()->item->is_in_predicate())
+  {
+    in_subs= (Item_in_subselect*) select_lex->master_unit()->item;
+    if (in_subs->create_in_to_exists_cond(this))
+      return true;
+  }
+  else
+    return false;
+
+  DBUG_ASSERT(in_subs->in_strategy); /* A strategy must be chosen earlier. */
+  DBUG_ASSERT(in_to_exists_where || in_to_exists_having);
+  DBUG_ASSERT(!in_to_exists_where || in_to_exists_where->fixed);
+  DBUG_ASSERT(!in_to_exists_having || in_to_exists_having->fixed);
+
+  /*
+    Compute and compare the costs of materialization and in-exists if both
+    strategies are possible and allowed by the user (checked during the prepare
+    phase.
+  */
+  if (in_subs->in_strategy & SUBS_MATERIALIZATION &&
+      in_subs->in_strategy & SUBS_IN_TO_EXISTS)
+  {
+    JOIN *outer_join;
+    JOIN *inner_join= this;
+    /* Number of (partial) rows of the outer JOIN filtered by the IN predicate. */
+    double outer_record_count;
+    /* Number of unique value combinations filtered by the IN predicate. */
+    double outer_lookup_keys;
+    /* Cost and row count of the unmodified subquery. */
+    double inner_read_time_1, inner_record_count_1;
+    /* Cost of the subquery with injected IN-EXISTS predicates. */
+    double inner_read_time_2;
+    /* The cost to compute IN via materialization. */
+    double materialize_strategy_cost;
+    /* The cost of the IN->EXISTS strategy. */
+    double in_exists_strategy_cost;
+    double dummy;
+
+    /*
+      A. Estimate the number of rows of the outer table that will be filtered
+      by the IN predicate.
+    */
+    outer_join= unit->outer_select() ? unit->outer_select()->join : NULL;
+    if (outer_join)
+    {
+      uint outer_partial_plan_len;
+      /*
+        Make_cond_for_table is called for predicates only in the WHERE/ON
+        clauses. In all other cases, predicates are not pushed to any
+        JOIN_TAB, and their joi_tab_idx remains MAX_TABLES. Such predicates
+        are evaluated for each complete row of the outer join.
+      */
+      outer_partial_plan_len= (in_subs->get_join_tab_idx() == MAX_TABLES) ?
+                               outer_join->tables :
+                               in_subs->get_join_tab_idx() + 1;
+      outer_join->get_partial_join_cost(outer_partial_plan_len, &dummy,
+                                        &outer_record_count);
+      if (outer_join->tables > outer_join->const_tables)
+        outer_lookup_keys= prev_record_reads(outer_join->best_positions,
+                                             outer_partial_plan_len,
+                                             in_subs->used_tables());
+      else
+      {
+        /* If all tables are constant, positions is undefined. */
+        outer_lookup_keys= 1;
+      }
+    }
+    else
+    {
+      /*
+        TODO: outer_join can be NULL for DELETE statements.
+        How to compute its cost?
+      */
+      outer_record_count= 1;
+      outer_lookup_keys=1;
+    }
+    /*
+      There cannot be more lookup keys than the total number of records.
+      TODO: this a temporary solution until we find a better way to compute
+      get_partial_join_cost() and prev_record_reads() in a consitent manner,
+      where it is guaranteed that (outer_lookup_keys <= outer_record_count).
+    */
+    if (outer_lookup_keys > outer_record_count)
+      outer_lookup_keys= outer_record_count;
+
+    /*
+      B. Estimate the cost and number of records of the subquery both
+      unmodified, and with injected IN->EXISTS predicates.
+    */
+    inner_read_time_1= inner_join->best_read;
+    inner_record_count_1= inner_join->record_count;
+
+    if (in_to_exists_where && const_tables != tables)
+    {
+      /*
+        Re-optimize and cost the subquery taking into account the IN-EXISTS
+        conditions.
+      */
+      reopt_result= reoptimize(in_to_exists_where, join_tables, &save_qep);
+      if (reopt_result == REOPT_ERROR)
+        return TRUE;
+
+      /* Get the cost of the modified IN-EXISTS plan. */
+      inner_read_time_2= inner_join->best_read;
+
+    }
+    else
+    {
+      /* Reoptimization would not produce any better plan. */
+      inner_read_time_2= inner_read_time_1;
+    }
+
+    /*
+      C. Compute execution costs.
+    */
+    /* C.1 Compute the cost of the materialization strategy. */
+    uint rowlen= get_tmp_table_rec_length(unit->first_select()->item_list);
+    /* The cost of writing one row into the temporary table. */
+    double write_cost= get_tmp_table_write_cost(thd, inner_record_count_1,
+                                                rowlen);
+    /* The cost of a lookup into the unique index of the materialized table. */
+    double lookup_cost= get_tmp_table_lookup_cost(thd, inner_record_count_1,
+                                                  rowlen);
+    /*
+      The cost of executing the subquery and storing its result in an indexed
+      temporary table.
+    */
+    double materialization_cost= inner_read_time_1 +
+                                 write_cost * inner_record_count_1;
+
+    materialize_strategy_cost= materialization_cost +
+                               outer_record_count * lookup_cost;
+
+    /* C.2 Compute the cost of the IN=>EXISTS strategy. */
+    in_exists_strategy_cost= outer_lookup_keys * inner_read_time_2;
+
+    /* C.3 Compare the costs and choose the cheaper strategy. */
+    if (materialize_strategy_cost >= in_exists_strategy_cost)
+      in_subs->in_strategy&= ~SUBS_MATERIALIZATION;
+    else
+      in_subs->in_strategy&= ~SUBS_IN_TO_EXISTS;
+  }
+
+  /*
+    If (1) materialization is a possible strategy based on semantic analysis
+    during the prepare phase, then if
+      (2) it is more expensive than the IN->EXISTS transformation, and
+      (3) it is not possible to create usable indexes for the materialization
+          strategy,
+      fall back to IN->EXISTS.
+    otherwise
+      use materialization.
+  */
+  if (in_subs->in_strategy & SUBS_MATERIALIZATION &&
+      in_subs->setup_mat_engine())
+  {
+    /*
+      If materialization was the cheaper or the only user-selected strategy,
+      but it is not possible to execute it due to limitations in the
+      implementation, fall back to IN-TO-EXISTS.
+    */
+    in_subs->in_strategy&= ~SUBS_MATERIALIZATION;
+    in_subs->in_strategy|= SUBS_IN_TO_EXISTS;
+  }
+
+  if (in_subs->in_strategy & SUBS_MATERIALIZATION)
+  {
+    /* Restore the original query plan used for materialization. */
+    if (reopt_result == REOPT_NEW_PLAN)
+      restore_query_plan(&save_qep);
+
+    /* TODO: should we set/unset this flag for both select_lex and its unit? */
+    in_subs->unit->uncacheable&= ~UNCACHEABLE_DEPENDENT;
+    select_lex->uncacheable&= ~UNCACHEABLE_DEPENDENT;
+
+    /*
+      Reset the "LIMIT 1" set in Item_exists_subselect::fix_length_and_dec.
+      TODO:
+      Currently we set the subquery LIMIT to infinity, and this is correct
+      because we forbid at parse time LIMIT inside IN subqueries (see
+      Item_in_subselect::test_limit). However, once we allow this, here
+      we should set the correct limit if given in the query.
+    */
+    in_subs->unit->global_parameters->select_limit= NULL;
+    in_subs->unit->set_limit(unit->global_parameters);
+    /*
+      Set the limit of this JOIN object as well, because normally its being
+      set in the beginning of JOIN::optimize, which was already done.
+    */
+    select_limit= in_subs->unit->select_limit_cnt;
+  }
+  else if (in_subs->in_strategy & SUBS_IN_TO_EXISTS)
+  {
+    if (reopt_result == REOPT_NONE && in_to_exists_where &&
+        const_tables != tables)
+    {
+      /*
+        The subquery was not reoptimized either because the user allowed only the
+        IN-EXISTS strategy, or because materialization was not possible based on
+        semantic analysis. Clenup the original plan and reoptimize.
+      */
+      for (uint i= 0; i < tables; i++)
+      {
+        join_tab[i].keyuse= NULL;
+        join_tab[i].checked_keys.clear_all();
+      }
+      if ((reopt_result= reoptimize(in_to_exists_where, join_tables, NULL)) ==
+          REOPT_ERROR)
+        return TRUE;
+    }
+
+    if (in_subs->inject_in_to_exists_cond(this))
+      return TRUE;
+  }
+  else
+    DBUG_ASSERT(FALSE);
+
+  return FALSE;
+}
+
+
+/**
+  Choose a query plan for a table-less subquery.
+
+  @notes
+
+  @retval FALSE     success.
+  @retval TRUE      error occurred.
+*/
+
+bool JOIN::choose_tableless_subquery_plan()
+{
+  DBUG_ASSERT(!tables_list || !tables);
+  if (select_lex->master_unit()->item)
+  {
+    DBUG_ASSERT(select_lex->master_unit()->item->type() ==
+                Item::SUBSELECT_ITEM);
+    Item_subselect *subs_predicate= select_lex->master_unit()->item;
+
+    /*
+      If the optimizer determined that his query has an empty result,
+      in most cases the subquery predicate is a known constant value -
+      either FALSE or NULL. The implementation of Item_subselect::reset()
+      determines which one.
+    */
+    if (zero_result_cause)
+    {
+      if (!implicit_grouping)
+      {
+        /*
+          Both group by queries and non-group by queries without aggregate
+          functions produce empty subquery result.
+        */
+        subs_predicate->reset();
+        subs_predicate->make_const();
+        return FALSE;
+      }
+
+      /* TODO:
+         A further optimization is possible when a non-group query with
+         MIN/MAX/COUNT is optimized by opt_sum_query. Then, if there are
+         only MIN/MAX functions over an empty result set, the subquery
+         result is a NULL value/row, thus the value of subs_predicate is
+         NULL.
+      */
+    }
+
+    if (subs_predicate->is_in_predicate())
+    {
+      Item_in_subselect *in_subs;
+      in_subs= (Item_in_subselect*) subs_predicate;
+      in_subs->in_strategy= SUBS_IN_TO_EXISTS;
+      if (in_subs->create_in_to_exists_cond(this) ||
+          in_subs->inject_in_to_exists_cond(this))
+        return TRUE;
+      tmp_having= having;
+    }
+  }
+  return FALSE;
+}
+
diff --git a/sql/share/errmsg.txt b/sql/share/errmsg.txt
index 853c9fac56e..0b4fed2be4b 100644
--- a/sql/share/errmsg.txt
+++ b/sql/share/errmsg.txt
@@ -6251,4 +6251,5 @@ ER_BAD_OPTION_VALUE
         eng "Incorrect value '%-.64s' for option '%-.64s'"
 ER_CANT_DO_ONLINE
         eng "Can't execute the given '%s' command as online"
-
+ER_ILLEGAL_SUBQUERY_OPTIMIZER_SWITCHES
+        eng "At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'."
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index fa495a776e1..31b5a703b19 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -8140,6 +8140,29 @@ insert_fields(THD *thd, Name_resolution_context *context, const char *db_name,
 }
 
 
+/**
+  Wrap Item_ident
+
+  @param thd             thread handle
+  @param conds           pointer to the condition which should be wrapped
+*/
+
+void wrap_ident(THD *thd, Item **conds)
+{
+  Item_direct_ref_to_ident *wrapper;
+  DBUG_ASSERT((*conds)->type() == Item::FIELD_ITEM || (*conds)->type() == Item::REF_ITEM);
+  Query_arena *arena= thd->stmt_arena, backup;
+  if (arena->is_conventional())
+    arena= 0;
+  else
+    thd->set_n_backup_active_arena(arena, &backup);
+  if ((wrapper= new Item_direct_ref_to_ident((Item_ident *)(*conds))))
+    (*conds)= (Item*) wrapper;
+  if (arena)
+    thd->restore_active_arena(arena, &backup);
+}
+
+
 /*
   Fix all conditions and outer join expressions.
 
@@ -8203,6 +8226,12 @@ int setup_conds(THD *thd, TABLE_LIST *tables, TABLE_LIST *leaves,
                  print_where(*conds,
                              "WHERE in setup_conds",
                              QT_ORDINARY););
+    /*
+      Wrap alone field in WHERE clause in case it will be outer field of subquery
+      which need persistent pointer on it, but conds could be changed by optimizer
+    */
+    if ((*conds)->type() == Item::FIELD_ITEM)
+      wrap_ident(thd, conds);
     if ((!(*conds)->fixed && (*conds)->fix_fields(thd, conds)) ||
 	(*conds)->check_cols(1))
       goto err_no_arena;
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index a5c06d2aa77..872c065e36a 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -2697,6 +2697,7 @@ void Query_arena::free_items()
   for (; free_list; free_list= next)
   {
     next= free_list->next;
+    DBUG_ASSERT(free_list != next);
     free_list->delete_self();
   }
   /* Postcondition: free_list is 0 */
@@ -3140,6 +3141,7 @@ void TMP_TABLE_PARAM::init()
   table_charset= 0;
   precomputed_group_by= 0;
   bit_fields_as_long= 0;
+  materialized_subquery= 0;
   skip_create_table= 0;
   DBUG_VOID_RETURN;
 }
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 904ffda5c85..c6f277f7bc7 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -2970,6 +2970,8 @@ public:
   uint  convert_blob_length;
   CHARSET_INFO *table_charset;
   bool schema_table;
+  /* TRUE if the temp table is created for subquery materialization. */
+  bool materialized_subquery;
   /*
     True if GROUP BY and its aggregate functions are already computed
     by a table access method (e.g. by loose index scan). In this case
@@ -2993,8 +2995,8 @@ public:
   TMP_TABLE_PARAM()
     :copy_field(0), group_parts(0),
      group_length(0), group_null_parts(0), convert_blob_length(0),
-     schema_table(0), precomputed_group_by(0), force_copy_fields(0),
-     bit_fields_as_long(0), skip_create_table(0)
+    schema_table(0), materialized_subquery(0), precomputed_group_by(0),
+    force_copy_fields(0), bit_fields_as_long(0), skip_create_table(0)
   {}
   ~TMP_TABLE_PARAM()
   {
@@ -3028,6 +3030,7 @@ public:
   virtual bool create_result_table(THD *thd, List<Item> *column_types,
                                    bool is_distinct, ulonglong options,
                                    const char *alias, bool bit_fields_as_long);
+  TMP_TABLE_PARAM *get_tmp_table_param() { return &tmp_table_param; }
 };
 
 /* Base subselect interface class */
@@ -3091,7 +3094,7 @@ protected:
   void reset();
 
 public:
-  select_materialize_with_stats() {}
+  select_materialize_with_stats() { tmp_table_param.init(); }
   virtual bool create_result_table(THD *thd, List<Item> *column_types,
                                    bool is_distinct, ulonglong options,
                                    const char *alias, bool bit_fields_as_long);
diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index e2cb17090a1..afda3070f08 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -93,6 +93,10 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
     }
   }
 
+  /* Apply the IN=>EXISTS transformation to all subqueries and optimize them. */
+  if (select_lex->optimize_unflattened_subqueries())
+    DBUG_RETURN(TRUE);
+
   const_cond= (!conds || conds->const_item());
   safe_update=test(thd->options & OPTION_SAFE_UPDATES);
   if (safe_update && const_cond)
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 3b655bac5af..29455c1b405 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -1684,6 +1684,31 @@ void st_select_lex_node::include_down(st_select_lex_node *upper)
   slave= 0;
 }
 
+
+void st_select_lex_node::add_slave(st_select_lex_node *slave_arg)
+{
+  for (; slave; slave= slave->next)
+    if (slave == slave_arg)
+      return;
+
+  if (slave)
+  {
+    st_select_lex_node *slave_arg_slave= slave_arg->slave;
+    /* Insert in the front of list of slaves if any. */
+    slave_arg->include_neighbour(slave);
+    /* include_neighbour() sets slave_arg->slave=0, restore it. */
+    slave_arg->slave= slave_arg_slave;
+    /* Count on include_neighbour() setting the master. */
+    DBUG_ASSERT(slave_arg->master == this);
+  }
+  else
+  {
+    slave= slave_arg;
+    slave_arg->master= this;
+  }
+}
+
+
 /*
   include on level down (but do not link)
 
@@ -1735,17 +1760,29 @@ void st_select_lex_node::fast_exclude()
   
 }
 
+
 /*
-  excluding select_lex structure (except first (first select can't be
+  Exclude a node from the tree lex structure, but leave it in the global
+  list of nodes.
+*/
+
+void st_select_lex_node::exclude_from_tree()
+{
+  if ((*prev= next))
+    next->prev= prev;
+}
+
+
+/*
+  Exclude select_lex structure (except first (first select can't be
   deleted, because it is most upper select))
 */
 void st_select_lex_node::exclude()
 {
-  //exclude from global list
+  /* exclude from global list */
   fast_exclude();
-  //exclude from other structures
-  if ((*prev= next))
-    next->prev= prev;
+  /* exclude from other structures */
+  exclude_from_tree();
   /* 
      We do not need following statements, because prev pointer of first 
      list element point to master->slave
@@ -2147,8 +2184,8 @@ void st_select_lex::print_limit(THD *thd,
                     select_limit == 1, and there should be no offset_limit.
                   */
                   (((subs_type == Item_subselect::IN_SUBS) &&
-                    ((Item_in_subselect*)item)->exec_method ==
-                    Item_in_subselect::MATERIALIZATION) ?
+                    ((Item_in_subselect*)item)->in_strategy &
+                    SUBS_MATERIALIZATION) ?
                    TRUE :
                    (select_limit->val_int() == 1LL) &&
                    offset_limit == 0));
@@ -3078,6 +3115,70 @@ bool st_select_lex::add_index_hint (THD *thd, char *str, uint length)
                                             str, length));
 }
 
+
+bool st_select_lex::optimize_unflattened_subqueries()
+{
+  for (SELECT_LEX_UNIT *un= first_inner_unit(); un; un= un->next_unit())
+  {
+    Item_subselect *subquery_predicate= un->item;
+    if (subquery_predicate)
+    {
+      for (SELECT_LEX *sl= un->first_select(); sl; sl= sl->next_select())
+      {
+        JOIN *inner_join= sl->join;
+        SELECT_LEX *save_select= un->thd->lex->current_select;
+        ulonglong save_options;
+        int res;
+        /* We need only 1 row to determine existence */
+        un->set_limit(un->global_parameters);
+        un->thd->lex->current_select= sl;
+        save_options= inner_join->select_options;
+        if (un->outer_select()->options & SELECT_DESCRIBE)
+        {
+          /* Optimize the subquery in the context of EXPLAIN. */
+          set_explain_type();
+          inner_join->select_options= options;
+        }
+        res= inner_join->optimize();
+        inner_join->select_options= save_options;
+        un->thd->lex->current_select= save_select;
+        if (res)
+          return TRUE;
+      }
+    }
+  }
+  return FALSE;
+}
+
+
+/**
+  Set the EXPLAIN type for this subquery.
+*/
+
+void st_select_lex::set_explain_type()
+{
+  SELECT_LEX *first= master_unit()->first_select();
+  /* drop UNCACHEABLE_EXPLAIN, because it is for internal usage only */
+  uint8 is_uncacheable= (uncacheable & ~UNCACHEABLE_EXPLAIN);
+
+  type= ((&master_unit()->thd->lex->select_lex == this) ?
+         (first_inner_unit() || next_select() ?
+          "PRIMARY" : "SIMPLE") :
+         ((this == first) ?
+          ((linkage == DERIVED_TABLE_TYPE) ?
+           "DERIVED" :
+           ((is_uncacheable & UNCACHEABLE_DEPENDENT) ?
+            "DEPENDENT SUBQUERY" :
+            (is_uncacheable ? "UNCACHEABLE SUBQUERY" :
+             "SUBQUERY"))) :
+          ((is_uncacheable & UNCACHEABLE_DEPENDENT) ?
+           "DEPENDENT UNION":
+           is_uncacheable ? "UNCACHEABLE UNION":
+           "UNION")));
+  options|= SELECT_DESCRIBE;
+}
+
+
 /**
   A routine used by the parser to decide whether we are specifying a full
   partitioning or if only partitions to add or to split.
@@ -3095,4 +3196,3 @@ bool st_lex::is_partition_management() const
           (alter_info.flags == ALTER_ADD_PARTITION ||
            alter_info.flags == ALTER_REORGANIZE_PARTITION));
 }
-
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index b3dccb4b9bd..f0e99fdc289 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -442,10 +442,12 @@ public:
   virtual void init_query();
   virtual void init_select();
   void include_down(st_select_lex_node *upper);
+  void add_slave(st_select_lex_node *slave_arg);
   void include_neighbour(st_select_lex_node *before);
   void include_standalone(st_select_lex_node *sel, st_select_lex_node **ref);
   void include_global(st_select_lex_node **plink);
   void exclude();
+  void exclude_from_tree();
 
   virtual st_select_lex_unit* master_unit()= 0;
   virtual st_select_lex* outer_select()= 0;
@@ -846,6 +848,15 @@ public:
 
   void clear_index_hints(void) { index_hints= NULL; }
   bool is_part_of_union() { return master_unit()->is_union(); }
+  /*
+    Optimize all subqueries that have not been flattened into semi-joins.
+    This functionality is a method of SELECT_LEX instead of JOIN because
+    some SQL statements as DELETE do not have a corresponding JOIN object.
+  */
+  bool optimize_unflattened_subqueries();
+  /* Set the EXPLAIN type for this subquery. */
+  void set_explain_type();
+
 private:  
   /* current index hint kind. used in filling up index_hints */
   enum index_hint_type current_index_hint_type;
diff --git a/sql/sql_list.h b/sql/sql_list.h
index 2dade14f211..e90f16aeb99 100644
--- a/sql/sql_list.h
+++ b/sql/sql_list.h
@@ -260,7 +260,7 @@ public:
     list_node *node= first;
     list_node *list_first= list->first;
     elements=0;
-    while (node && node != list_first)
+    while (node->info && node != list_first)
     {
       prev= &node->next;
       node= node->next;
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index c23318975dc..4055b97cbed 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -55,21 +55,19 @@ static bool make_join_statistics(JOIN *join, TABLE_LIST *leaves, COND *conds,
 static bool update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,
                                 JOIN_TAB *join_tab,
                                 uint tables, COND *conds,
-                                COND_EQUAL *cond_equal,
                                 table_map table_map, SELECT_LEX *select_lex,
                                 st_sargable_param **sargables);
+static bool sort_and_filter_keyuse(DYNAMIC_ARRAY *keyuse);
 static int sort_keyuse(KEYUSE *a,KEYUSE *b);
 static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
 			       table_map used_tables);
-bool choose_plan(JOIN *join,table_map join_tables);
-
 void best_access_path(JOIN *join, JOIN_TAB *s, 
                              table_map remaining_tables, uint idx, 
                              bool disable_jbuf, double record_count,
                              POSITION *pos, POSITION *loose_scan_pos);
 static void optimize_straight_join(JOIN *join, table_map join_tables);
 static bool greedy_search(JOIN *join, table_map remaining_tables,
-                             uint depth, uint prune_level);
+                          uint depth, uint prune_level);
 static bool best_extension_by_limited_search(JOIN *join,
                                              table_map remaining_tables,
                                              uint idx, double record_count,
@@ -86,7 +84,6 @@ static int join_tab_cmp_embedded_first(const void *emb, const void* ptr1, const
 static bool find_best(JOIN *join,table_map rest_tables,uint index,
 		      double record_count,double read_time);
 static uint cache_record_length(JOIN *join,uint index);
-static double prev_record_reads(JOIN *join, uint idx, table_map found_ref);
 static bool get_best_combination(JOIN *join);
 static store_key *get_store_key(THD *thd,
 				KEYUSE *keyuse, table_map used_tables,
@@ -174,13 +171,16 @@ static int join_ft_read_first(JOIN_TAB *tab);
 static int join_ft_read_next(READ_RECORD *info);
 int join_read_always_key_or_null(JOIN_TAB *tab);
 int join_read_next_same_or_null(READ_RECORD *info);
-static COND *make_cond_for_table(Item *cond,table_map table,
+static COND *make_cond_for_table(THD *thd, Item *cond,table_map table,
                                  table_map used_table,
+                                 uint join_tab_idx_arg,
                                  bool exclude_expensive_cond,
                                  bool retain_ref_cond);
-static COND *make_cond_for_table_from_pred(Item *root_cond, Item *cond,
+static COND *make_cond_for_table_from_pred(THD *thd, Item *root_cond,
+                                           Item *cond,
                                            table_map tables,
                                            table_map used_table,
+                                           uint join_tab_idx_arg,
                                            bool exclude_expensive_cond,
                                            bool retain_ref_cond);
 
@@ -235,8 +235,6 @@ static bool update_sum_func(Item_sum **func);
 static void select_describe(JOIN *join, bool need_tmp_table,bool need_order,
 			    bool distinct, const char *message=NullS);
 static void add_group_and_distinct_keys(JOIN *join, JOIN_TAB *join_tab);
-void get_partial_join_cost(JOIN *join, uint idx, double *read_time_arg,
-                           double *record_count_arg);
 static uint make_join_orderinfo(JOIN *join);
 static int
 join_read_record_no_init(JOIN_TAB *tab);
@@ -580,6 +578,13 @@ JOIN::prepare(Item ***rref_pointer_array,
     thd->where="having clause";
     thd->lex->allow_sum_func|= 1 << select_lex_arg->nest_level;
     select_lex->having_fix_field= 1;
+    /*
+      Wrap alone field in HAVING clause in case it will be outer field of subquery
+      which need persistent pointer on it, but having could be changed by optimizer
+    */
+    if (having->type() == Item::REF_ITEM &&
+        ((Item_ref *)having)->ref_type() == Item_ref::REF)
+      wrap_ident(thd, &having);
     bool having_fix_rc= (!having->fixed &&
 			 (having->fix_fields(thd, &having) ||
 			  having->check_cols(1)));
@@ -882,6 +887,7 @@ JOIN::optimize()
                            "Impossible HAVING" : "Impossible WHERE";
       tables= 0;
       error= 0;
+      choose_tableless_subquery_plan();
       goto setup_subq_exit;
     }
   }
@@ -926,12 +932,13 @@ JOIN::optimize()
     */
     if ((res=opt_sum_query(select_lex->leaf_tables, all_fields, conds)))
     {
-      if (res == HA_ERR_KEY_NOT_FOUND)
+      if (res == HA_ERR_KEY_NOT_FOUND || res < 0)
       {
         DBUG_PRINT("info",("No matching min/max row"));
 	zero_result_cause= "No matching min/max row";
         tables= 0;
 	error=0;
+        choose_tableless_subquery_plan();
         goto setup_subq_exit;
       }
       if (res > 1)
@@ -940,14 +947,7 @@ JOIN::optimize()
         DBUG_PRINT("error",("Error from opt_sum_query"));
         DBUG_RETURN(1);
       }
-      if (res < 0)
-      {
-        DBUG_PRINT("info",("No matching min/max row"));
-        zero_result_cause= "No matching min/max row";
-        tables= 0;
-        error=0;
-        goto setup_subq_exit;
-      }
+
       DBUG_PRINT("info",("Select tables optimized away"));
       zero_result_cause= "Select tables optimized away";
       tables_list= 0;				// All tables resolved
@@ -965,24 +965,22 @@ JOIN::optimize()
       if (conds && !(thd->lex->describe & DESCRIBE_EXTENDED))
       {
         COND *table_independent_conds=
-          make_cond_for_table(conds, PSEUDO_TABLE_BITS, 0, FALSE, FALSE);
+          make_cond_for_table(thd, conds, PSEUDO_TABLE_BITS, 0, MAX_TABLES,
+                              FALSE, FALSE);
         DBUG_EXECUTE("where",
                      print_where(table_independent_conds,
                                  "where after opt_sum_query()",
                                  QT_ORDINARY););
         conds= table_independent_conds;
       }
-      goto setup_subq_exit;
     }
   }
   if (!tables_list)
   {
     DBUG_PRINT("info",("No tables"));
     error= 0;
-    /* Create all structures needed for materialized subquery execution. */
-    if (setup_subquery_materialization())
-      DBUG_RETURN(1);
-    DBUG_RETURN(0);
+    choose_tableless_subquery_plan();
+    goto setup_subq_exit;
   }
   error= -1;					// Error is sent to client
   sort_by_table= get_sort_by_table(order, group_list, select_lex->leaf_tables);
@@ -1374,8 +1372,7 @@ JOIN::optimize()
   if (!(select_options & SELECT_DESCRIBE))
     init_ftfuncs(thd, select_lex, test(order));
 
-  /* Create all structures needed for materialized subquery execution. */
-  if (setup_subquery_materialization())
+  if (optimize_unflattened_subqueries())
     DBUG_RETURN(1);
   
   int res;
@@ -1479,6 +1476,34 @@ JOIN::optimize()
   if (join_tab->is_using_loose_index_scan())
     tmp_table_param.precomputed_group_by= TRUE;
 
+  error= 0;
+  DBUG_RETURN(0);
+
+setup_subq_exit:
+  /*
+    Even with zero matching rows, subqueries in the HAVING clause may
+    need to be evaluated if there are aggregate functions in the query.
+  */
+  if (optimize_unflattened_subqueries())
+    DBUG_RETURN(1);
+  error= 0;
+  DBUG_RETURN(0);
+}
+
+
+/**
+  Create and initialize objects neeed for the execution of a query plan.
+  Evaluate constant expressions not evaluated during optimization.
+*/
+
+int JOIN::init_execution()
+{
+  DBUG_ENTER("JOIN::init_execution");
+
+  DBUG_ASSERT(optimized);
+  DBUG_ASSERT(!(select_options & SELECT_DESCRIBE));
+  initialized= true;
+
   /* Create a tmp table if distinct or if the sort is too complicated */
   if (need_tmp)
   {
@@ -1511,7 +1536,7 @@ JOIN::optimize()
 			   select_options,
                            tmp_rows_limit,
 			   (char *) "")))
-		{
+    {
       DBUG_RETURN(1);
     }
 
@@ -1597,19 +1622,6 @@ JOIN::optimize()
       DBUG_RETURN(-1);                         /* purecov: inspected */
   }
 
-  error= 0;
-  DBUG_RETURN(0);
-
-setup_subq_exit:
-  /*
-    Even with zero matching rows, subqueries in the HAVING clause may
-    need to be evaluated if there are aggregate functions in the
-    query. If we have planned to materialize the subquery, we need to
-    set it up properly before prematurely leaving optimize().
-  */
-  if (setup_subquery_materialization())
-    DBUG_RETURN(1);
-  error= 0;
   DBUG_RETURN(0);
 }
 
@@ -1958,6 +1970,16 @@ JOIN::exec()
   if (tables)
     thd->limit_found_rows= 0;
 
+  /*
+    Evaluate expensive constant conditions that were not evaluated during
+    optimization. Do not evaluate them for EXPLAIN statements as these
+    condtions may be arbitrarily costly, and because the optimize phase
+    might not have produced a complete executable plan for EXPLAINs.
+  */
+  if (exec_const_cond && !(select_options & SELECT_DESCRIBE) &&
+      !exec_const_cond->val_int())
+    zero_result_cause= "Impossible WHERE noticed after reading const tables";
+
   if (zero_result_cause)
   {
     (void) return_zero_rows(this, result, select_lex->leaf_tables,
@@ -1965,10 +1987,31 @@ JOIN::exec()
 			    send_row_on_empty_set(),
 			    select_options,
 			    zero_result_cause,
-			    having);
+			    having ? having : tmp_having);
     DBUG_VOID_RETURN;
   }
 
+  /*
+    Evaluate all constant expressions with subqueries in the ORDER/GROUP clauses
+    to make sure that all subqueries return a single row. The evaluation itself
+    will trigger an error if that is not the case.
+  */
+  if (exec_const_order_group_cond.elements &&
+      !(select_options & SELECT_DESCRIBE))
+  {
+    List_iterator_fast<Item> const_item_it(exec_const_order_group_cond);
+    Item *cur_const_item;
+    while ((cur_const_item= const_item_it++))
+    {
+      cur_const_item->val_str(&cur_const_item->str_value);
+      if (thd->is_error())
+      {
+        error= thd->is_error();
+        DBUG_VOID_RETURN;
+      }
+    }
+  }
+
   if ((this->select_lex->options & OPTION_SCHEMA_TABLE) &&
       get_schema_tables_result(this, PROCESSED_BY_JOIN_EXEC))
     DBUG_VOID_RETURN;
@@ -2007,6 +2050,9 @@ JOIN::exec()
     DBUG_VOID_RETURN;
   }
 
+  if (!initialized && init_execution())
+    DBUG_VOID_RETURN;
+
   JOIN *curr_join= this;
   List<Item> *curr_all_fields= &all_fields;
   List<Item> *curr_fields_list= &fields_list;
@@ -2337,9 +2383,10 @@ JOIN::exec()
       table_map used_tables= (curr_join->const_table_map |
 			      curr_table->table->map);
 
-      Item* sort_table_cond= make_cond_for_table(curr_join->tmp_having,
+      Item* sort_table_cond= make_cond_for_table(thd, curr_join->tmp_having,
 						 used_tables,
-						 (table_map)0, FALSE, FALSE);
+						 (table_map)0, MAX_TABLES,
+						 FALSE, FALSE);
       if (sort_table_cond)
       {
 	if (!curr_table->select)
@@ -2375,9 +2422,10 @@ JOIN::exec()
 	DBUG_EXECUTE("where",print_where(curr_table->select->cond,
 					 "select and having",
                                          QT_ORDINARY););
-	curr_join->tmp_having= make_cond_for_table(curr_join->tmp_having,
+	curr_join->tmp_having= make_cond_for_table(thd, curr_join->tmp_having,
 						   ~ (table_map) 0,
-						   ~used_tables, FALSE, FALSE);
+						   ~used_tables, MAX_TABLES,
+						   FALSE, FALSE);
 	DBUG_EXECUTE("where",print_where(curr_join->tmp_having,
                                          "having after sort",
                                          QT_ORDINARY););
@@ -2727,51 +2775,6 @@ err:
 }
 
 
-/**
-  Setup for execution all subqueries of a query, for which the optimizer
-  chose hash semi-join.
-
-  @details Iterate over all subqueries of the query, and if they are under an
-  IN predicate, and the optimizer chose to compute it via hash semi-join:
-  - try to initialize all data structures needed for the materialized execution
-    of the IN predicate,
-  - if this fails, then perform the IN=>EXISTS transformation which was
-    previously blocked during JOIN::prepare.
-
-  This method is part of the "code generation" query processing phase.
-
-  This phase must be called after substitute_for_best_equal_field() because
-  that function may replace items with other items from a multiple equality,
-  and we need to reference the correct items in the index access method of the
-  IN predicate.
-
-  @return Operation status
-  @retval FALSE     success.
-  @retval TRUE      error occurred.
-*/
-
-bool JOIN::setup_subquery_materialization()
-{
-  for (SELECT_LEX_UNIT *un= select_lex->first_inner_unit(); un;
-       un= un->next_unit())
-  {
-    for (SELECT_LEX *sl= un->first_select(); sl; sl= sl->next_select())
-    {
-      Item_subselect *subquery_predicate= sl->master_unit()->item;
-      if (subquery_predicate &&
-          subquery_predicate->substype() == Item_subselect::IN_SUBS)
-      {
-        Item_in_subselect *in_subs= (Item_in_subselect*) subquery_predicate;
-        if (in_subs->exec_method == Item_in_subselect::MATERIALIZATION &&
-            in_subs->setup_engine())
-          return TRUE;
-      }
-    }
-  }
-  return FALSE;
-}
-
-
 /*****************************************************************************
   Create JOIN_TABS, make a guess about the table types,
   Approximate how many records will be used in each table
@@ -2997,10 +3000,14 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
   }
 
   if (conds || outer_join)
+  {
     if (update_ref_and_keys(join->thd, keyuse_array, stat, join->tables,
-                            conds, join->cond_equal,
-                            ~outer_join, join->select_lex, &sargables))
+                            conds, ~outer_join, join->select_lex, &sargables))
       goto error;
+    if (keyuse_array->elements && sort_and_filter_keyuse(keyuse_array))
+      goto error;
+    DBUG_EXECUTE("opt", print_keyuse_array(keyuse_array););
+  }
 
   join->const_table_map= no_rows_const_tables;
   join->const_tables= const_count;
@@ -3307,8 +3314,12 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables_arg, COND *conds,
   {
     memcpy((uchar*) join->best_positions,(uchar*) join->positions,
 	   sizeof(POSITION)*join->const_tables);
+    join->record_count= 1.0;
     join->best_read=1.0;
   }
+  if (join->choose_subquery_plan(all_table_map & ~join->const_table_map))
+    goto error;
+
   /* Generate an execution plan from the found optimal join order. */
   DBUG_RETURN(join->thd->killed || get_best_combination(join));
 
@@ -4322,11 +4333,10 @@ static void add_key_fields_for_nj(JOIN *join, TABLE_LIST *nested_join_table,
 
 static bool
 update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
-                    uint tables, COND *cond, COND_EQUAL *cond_equal,
-                    table_map normal_tables, SELECT_LEX *select_lex,
-                    SARGABLE_PARAM **sargables)
+                    uint tables, COND *cond, table_map normal_tables,
+                    SELECT_LEX *select_lex, SARGABLE_PARAM **sargables)
 {
-  uint	and_level,i,found_eq_constant;
+  uint	and_level,i;
   KEY_FIELD *key_fields, *end, *field;
   uint sz;
   uint m= max(select_lex->max_equal_elems,1);
@@ -4422,73 +4432,81 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
       return TRUE;
   }
 
-  /*
-    Sort the array of possible keys and remove the following key parts:
-    - ref if there is a keypart which is a ref and a const.
-      (e.g. if there is a key(a,b) and the clause is a=3 and b=7 and b=t2.d,
-      then we skip the key part corresponding to b=t2.d)
-    - keyparts without previous keyparts
-      (e.g. if there is a key(a,b,c) but only b < 5 (or a=2 and c < 3) is
-      used in the query, we drop the partial key parts from consideration).
-    Special treatment for ft-keys.
-  */
-  if (keyuse->elements)
-  {
-    KEYUSE key_end,*prev,*save_pos,*use;
-
-    my_qsort(keyuse->buffer,keyuse->elements,sizeof(KEYUSE),
-	  (qsort_cmp) sort_keyuse);
-
-    bzero((char*) &key_end,sizeof(key_end));    /* Add for easy testing */
-    if (insert_dynamic(keyuse,(uchar*) &key_end))
-      return TRUE;
-
-    use=save_pos=dynamic_element(keyuse,0,KEYUSE*);
-    prev= &key_end;
-    found_eq_constant=0;
-    for (i=0 ; i < keyuse->elements-1 ; i++,use++)
-    {
-      if (!use->is_for_hash_join())
-      {
-        if (!use->used_tables && use->optimize != KEY_OPTIMIZE_REF_OR_NULL)
-	  use->table->const_key_parts[use->key]|= use->keypart_map;
-        if (use->keypart != FT_KEYPART)
-        {
-	  if (use->key == prev->key && use->table == prev->table)
-	  {
-	    if (prev->keypart+1 < use->keypart ||
-	        (prev->keypart == use->keypart && found_eq_constant))
-	      continue;				/* remove */
-	  }
-	  else if (use->keypart != 0)		// First found must be 0
-	    continue;
-        }
-
-        prev= use;
-        found_eq_constant= !use->used_tables;
-        use->table->reginfo.join_tab->checked_keys.set_bit(use->key);
-      }
-      /*
-        Old gcc used a memcpy(), which is undefined if save_pos==use:
-        http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19410
-        http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39480
-        This also disables a valgrind warning, so better to have the test.
-      */
-      if (save_pos != use)
-        *save_pos= *use;
-      /* Save ptr to first use */
-      if (!use->table->reginfo.join_tab->keyuse)
-	use->table->reginfo.join_tab->keyuse= save_pos;
-      save_pos++;
-    }
-    i=(uint) (save_pos-(KEYUSE*) keyuse->buffer);
-    VOID(set_dynamic(keyuse,(uchar*) &key_end,i));
-    keyuse->elements=i;
-  }
-  DBUG_EXECUTE("opt", print_keyuse_array(keyuse););
   return FALSE;
 }
 
+
+/**
+  Sort the array of possible keys and remove the following key parts:
+  - ref if there is a keypart which is a ref and a const.
+    (e.g. if there is a key(a,b) and the clause is a=3 and b=7 and b=t2.d,
+    then we skip the key part corresponding to b=t2.d)
+  - keyparts without previous keyparts
+    (e.g. if there is a key(a,b,c) but only b < 5 (or a=2 and c < 3) is
+    used in the query, we drop the partial key parts from consideration).
+  Special treatment for ft-keys.
+*/
+
+static bool sort_and_filter_keyuse(DYNAMIC_ARRAY *keyuse)
+{
+  KEYUSE key_end, *prev, *save_pos, *use;
+  uint found_eq_constant, i;
+
+  DBUG_ASSERT(keyuse->elements);
+
+  my_qsort(keyuse->buffer, keyuse->elements, sizeof(KEYUSE),
+           (qsort_cmp) sort_keyuse);
+
+  bzero((char*) &key_end, sizeof(key_end));    /* Add for easy testing */
+  if (insert_dynamic(keyuse, (uchar*) &key_end))
+    return TRUE;
+
+  use= save_pos= dynamic_element(keyuse,0,KEYUSE*);
+  prev= &key_end;
+  found_eq_constant= 0;
+  for (i=0 ; i < keyuse->elements-1 ; i++,use++)
+  {
+    if (!use->is_for_hash_join())
+    {
+      if (!use->used_tables && use->optimize != KEY_OPTIMIZE_REF_OR_NULL)
+        use->table->const_key_parts[use->key]|= use->keypart_map;
+      if (use->keypart != FT_KEYPART)
+      {
+        if (use->key == prev->key && use->table == prev->table)
+        {
+          if (prev->keypart+1 < use->keypart ||
+              (prev->keypart == use->keypart && found_eq_constant))
+            continue;				/* remove */
+        }
+        else if (use->keypart != 0)		// First found must be 0
+          continue;
+      }
+
+      prev= use;
+      found_eq_constant= !use->used_tables;
+      use->table->reginfo.join_tab->checked_keys.set_bit(use->key);
+    }
+    /*
+      Old gcc used a memcpy(), which is undefined if save_pos==use:
+      http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19410
+      http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39480
+      This also disables a valgrind warning, so better to have the test.
+    */
+    if (save_pos != use)
+      *save_pos= *use;
+    /* Save ptr to first use */
+    if (!use->table->reginfo.join_tab->keyuse)
+      use->table->reginfo.join_tab->keyuse= save_pos;
+    save_pos++;
+  }
+  i= (uint) (save_pos-(KEYUSE*) keyuse->buffer);
+  VOID(set_dynamic(keyuse,(uchar*) &key_end,i));
+  keyuse->elements= i;
+
+  return FALSE;
+}
+
+
 /**
   Update some values in keyuse for faster choose_plan() loop.
 */
@@ -4778,8 +4796,8 @@ best_access_path(JOIN      *join,
             if (!(keyuse->used_tables & ~join->const_table_map))
               const_part|= keyuse->keypart_map;
 
-            double tmp2= prev_record_reads(join, idx, (found_ref |
-                                                      keyuse->used_tables));
+            double tmp2= prev_record_reads(join->positions, idx,
+                                           (found_ref | keyuse->used_tables));
             if (tmp2 < best_prev_record_reads)
             {
               best_part_found_ref= keyuse->used_tables & ~join->const_table_map;
@@ -4819,7 +4837,7 @@ best_access_path(JOIN      *join,
           Really, there should be records=0.0 (yes!)
           but 1.0 would be probably safer
         */
-        tmp= prev_record_reads(join, idx, found_ref);
+        tmp= prev_record_reads(join->positions, idx, found_ref);
         records= 1.0;
       }
       else
@@ -4834,7 +4852,7 @@ best_access_path(JOIN      *join,
           max_key_part= (uint) ~0;
           if ((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY)) == HA_NOSAME)
           {
-            tmp = prev_record_reads(join, idx, found_ref);
+            tmp = prev_record_reads(join->positions, idx, found_ref);
             records=1.0;
           }
           else
@@ -5566,6 +5584,7 @@ optimize_straight_join(JOIN *join, table_map join_tables)
     read_time+= record_count;  // We have to make a temp table
   memcpy((uchar*) join->best_positions, (uchar*) join->positions,
          sizeof(POSITION)*idx);
+  join->record_count= record_count;
   join->best_read= read_time;
 }
 
@@ -5747,40 +5766,45 @@ greedy_search(JOIN      *join,
 }
 
 
-/*
-  Calculate a cost of given partial join order
+/**
+  Calculate a cost of given partial join order in join->positions.
  
-  SYNOPSIS
-    get_partial_join_cost()
-      join               IN    Join to use. join->positions holds the
-                               partial join order
-      idx                IN    # tables in the partial join order
-      read_time_arg      OUT   Store read time here 
-      record_count_arg   OUT   Store record count here
+  @param n_tables[in]      # tables in the partial join order after the last
+                           constant table
+  @param read_time_arg[out]    store read time here 
+  @param record_count_arg[out] store record count here
 
-  DESCRIPTION
-
-    This is needed for semi-join materialization code. The idea is that 
-    we detect sj-materialization after we've put all sj-inner tables into
-    the join prefix
+  @note
+    When used by semi-join materialization code the idea is that we
+    detect sj-materialization after we've put all sj-inner tables into
+    the join prefix.
 
       prefix-tables semi-join-inner-tables  tN
                                              ^--we're here
 
     and we'll need to get the cost of prefix-tables prefix again.
+
+    When used with non-flattened subqueries, the method computes the
+    total cost of query plan.
+
+  @returns
+    read_time_arg and record_count_arg contain the computed cost.
 */
 
-void get_partial_join_cost(JOIN *join, uint n_tables, double *read_time_arg,
-                           double *record_count_arg)
+void JOIN::get_partial_join_cost(uint n_tables,
+                                 double *read_time_arg, double *record_count_arg)
 {
   double record_count= 1;
   double read_time= 0.0;
-  for (uint i= join->const_tables; i < n_tables + join->const_tables ; i++)
+
+  DBUG_ASSERT(n_tables <= tables);
+
+  for (uint i= const_tables; i < n_tables; i++)
   {
-    if (join->best_positions[i].records_read)
+    if (best_positions[i].records_read)
     {
-      record_count *= join->best_positions[i].records_read;
-      read_time += join->best_positions[i].read_time;
+      record_count *= best_positions[i].records_read;
+      read_time += best_positions[i].read_time;
     }
   }
   *read_time_arg= read_time;// + record_count / TIME_FOR_COMPARE;
@@ -5788,8 +5812,6 @@ void get_partial_join_cost(JOIN *join, uint n_tables, double *read_time_arg,
 }
 
 
-
-
 /**
   Find a good, possibly optimal, query execution plan (QEP) by a possibly
   exhaustive search.
@@ -6046,6 +6068,7 @@ best_extension_by_limited_search(JOIN      *join,
         {
           memcpy((uchar*) join->best_positions, (uchar*) join->positions,
                  sizeof(POSITION) * (idx + 1));
+          join->record_count= current_record_count;
           join->best_read= current_read_time - 0.001;
         }
         DBUG_EXECUTE("opt", print_plan(join, idx+1,
@@ -6234,8 +6257,9 @@ int JOIN_TAB::make_scan_filter()
                 *get_first_inner_table()->on_expr_ref : join->conds;
 
   if (cond &&
-      (tmp=make_cond_for_table(cond, join->const_table_map | table->map,
-			       table->map, FALSE, TRUE)))
+      (tmp= make_cond_for_table(join->thd, cond,
+                               join->const_table_map | table->map,
+			       table->map, MAX_TABLES, FALSE, TRUE)))
   {
      DBUG_EXECUTE("where",print_where(tmp,"cache", QT_ORDINARY););
      if (!(cache_select=
@@ -6347,12 +6371,12 @@ cache_record_length(JOIN *join,uint idx)
     Expected number of row combinations
 */
 
-static double
-prev_record_reads(JOIN *join, uint idx, table_map found_ref)
+double
+prev_record_reads(POSITION *positions, uint idx, table_map found_ref)
 {
   double found=1.0;
-  POSITION *pos_end= join->positions - 1;
-  for (POSITION *pos= join->positions + idx - 1; pos != pos_end; pos--)
+  POSITION *pos_end= positions - 1;
+  for (POSITION *pos= positions + idx - 1; pos != pos_end; pos--)
   {
     if (pos->table->table->map & found_ref)
     {
@@ -6854,7 +6878,7 @@ JOIN::make_simple_join(JOIN *parent, TABLE *temp_table)
 }
 
 
-inline void add_cond_and_fix(Item **e1, Item *e2)
+inline void add_cond_and_fix(THD *thd, Item **e1, Item *e2)
 {
   if (*e1)
   {
@@ -6864,7 +6888,7 @@ inline void add_cond_and_fix(Item **e1, Item *e2)
     if ((res= new Item_cond_and(*e1, e2)))
     {
       *e1= res;
-      res->quick_fix_field();
+      res->fix_fields(thd, 0);
       res->update_used_tables();
     }
   }
@@ -6968,14 +6992,14 @@ static void add_not_null_conds(JOIN *join)
             COND *new_cond= referred_tab->join == join ? 
                               referred_tab->select_cond :
                               join->outer_ref_cond;
-            add_cond_and_fix(&new_cond, notnull);
+            add_cond_and_fix(join->thd, &new_cond, notnull);
             if (referred_tab->join == join)
               referred_tab->set_select_cond(new_cond, __LINE__);
             else 
               join->outer_ref_cond= new_cond;
           }
           else
-            add_cond_and_fix(tab->first_inner->on_expr_ref, notnull);
+            add_cond_and_fix(join->thd, tab->first_inner->on_expr_ref, notnull);
         }
       }
     }
@@ -7151,24 +7175,27 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
            there inside the triggers.
       */
       {						// Check const tables
-        COND *const_cond=
-	  make_cond_for_table(cond,
+        join->exec_const_cond=
+	  make_cond_for_table(thd, cond,
                               join->const_table_map,
-                              (table_map) 0, TRUE, FALSE);
+                              (table_map) 0, MAX_TABLES, FALSE, FALSE);
         /* Add conditions added by add_not_null_conds(). */
         for (uint i= 0 ; i < join->const_tables ; i++)
-          add_cond_and_fix(&const_cond, join->join_tab[i].select_cond);
+          add_cond_and_fix(thd, &join->exec_const_cond,
+                           join->join_tab[i].select_cond);
 
-        DBUG_EXECUTE("where",print_where(const_cond,"constants", QT_ORDINARY););
+        DBUG_EXECUTE("where",print_where(join->exec_const_cond,"constants",
+					 QT_ORDINARY););
         for (JOIN_TAB *tab= join->join_tab+join->const_tables;
              tab < join->join_tab+join->tables ; tab++)
         {
           if (*tab->on_expr_ref)
           {
             JOIN_TAB *cond_tab= tab->first_inner;
-            COND *tmp= make_cond_for_table(*tab->on_expr_ref,
+            COND *tmp= make_cond_for_table(thd, *tab->on_expr_ref,
                                            join->const_table_map,
-					   (table_map) 0, FALSE, FALSE);
+					   (table_map) 0, MAX_TABLES,
+					   FALSE, FALSE);
             if (!tmp)
               continue;
             tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
@@ -7184,18 +7211,22 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
             cond_tab->select_cond->quick_fix_field();
           }       
         }
-        if (const_cond && !const_cond->val_int())
+
+        if (join->exec_const_cond && !join->exec_const_cond->is_expensive() &&
+            !join->exec_const_cond->val_int())
         {
-	  DBUG_PRINT("info",("Found impossible WHERE condition"));
-	  DBUG_RETURN(1);	 // Impossible const condition
+          DBUG_PRINT("info",("Found impossible WHERE condition"));
+          join->exec_const_cond= NULL;
+          DBUG_RETURN(1);	 // Impossible const condition
         }
 
-        COND *outer_ref_cond= make_cond_for_table(cond, 
+        COND *outer_ref_cond= make_cond_for_table(thd, cond, 
                                                   OUTER_REF_TABLE_BIT,
-                                                  (table_map) 0, FALSE, FALSE);
+                                                  (table_map) 0, MAX_TABLES,
+                                                  FALSE, FALSE);
         if (outer_ref_cond)
 	{
-          add_cond_and_fix(&outer_ref_cond, join->outer_ref_cond);
+          add_cond_and_fix(thd, &outer_ref_cond, join->outer_ref_cond);
           join->outer_ref_cond= outer_ref_cond;
         }
       }
@@ -7267,10 +7298,11 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
 
       tmp= NULL;
       if (cond)
-        tmp= make_cond_for_table(cond, used_tables, current_map, FALSE, FALSE);
+	tmp= make_cond_for_table(thd, cond, used_tables, current_map, i,
+                                 FALSE, FALSE);
       /* Add conditions added by add_not_null_conds(). */
       if (tab->select_cond)
-        add_cond_and_fix(&tmp, tab->select_cond);
+        add_cond_and_fix(thd, &tmp, tab->select_cond);
 
       is_hj= (tab->type == JT_REF || tab->type == JT_EQ_REF) &&
              (join->allowed_join_cache_types & JOIN_CACHE_HASHED_BIT) &&
@@ -7338,7 +7370,8 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
 	  if (thd->variables.engine_condition_pushdown && !first_inner_tab)
           {
             COND *push_cond= 
-              make_cond_for_table(tmp, current_map, current_map, FALSE, FALSE);
+              make_cond_for_table(thd, tmp, current_map, current_map,
+                                  MAX_TABLES, FALSE, FALSE);
             if (push_cond)
             {
               /* Push condition to handler */
@@ -7488,9 +7521,9 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
         if (*join_tab->on_expr_ref)
         {
           JOIN_TAB *cond_tab= join_tab->first_inner;
-          COND *tmp= make_cond_for_table(*join_tab->on_expr_ref,
+          COND *tmp= make_cond_for_table(thd, *join_tab->on_expr_ref,
                                          join->const_table_map,
-                                         (table_map) 0, FALSE, FALSE);
+                                         (table_map) 0, MAX_TABLES, FALSE, FALSE);
           if (!tmp)
             continue;
           tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
@@ -7509,6 +7542,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
       }
 
       /* Push down non-constant conditions from on expressions */
+      JOIN_TAB *first_tab= join->join_tab+join->const_tables;
       JOIN_TAB *last_tab= tab;
       while (first_inner_tab && first_inner_tab->last_inner == last_tab)
       {  
@@ -7520,14 +7554,15 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
 
         table_map used_tables2= (join->const_table_map |
                                  OUTER_REF_TABLE_BIT | RAND_TABLE_BIT);
-	for (tab= join->join_tab+join->const_tables; tab <= last_tab ; tab++)
+	for (tab= first_tab; tab <= last_tab ; tab++)
         {
           current_map= tab->table->map;
           used_tables2|= current_map;
-          COND *tmp_cond= make_cond_for_table(on_expr, used_tables2,
-                                              current_map, FALSE, FALSE);
+          COND *tmp_cond= make_cond_for_table(thd, on_expr, used_tables2,
+                                              current_map, (tab - first_tab),
+					      FALSE, FALSE);
           if (tab == first_inner_tab && tab->on_precond)
-            add_cond_and_fix(&tmp_cond, tab->on_precond);
+            add_cond_and_fix(thd, &tmp_cond, tab->on_precond);
           if (tmp_cond)
           {
             JOIN_TAB *cond_tab= tab < first_inner_tab ? first_inner_tab : tab;
@@ -9035,11 +9070,16 @@ remove_const(JOIN *join,ORDER *first_order, COND *cond,
       *simple_order=0;				// Must do a temp table to sort
     else if (!(order_tables & not_const_tables))
     {
-      if (order->item[0]->with_subselect && 
-          !(join->select_lex->options & SELECT_DESCRIBE))
-        order->item[0]->val_str(&order->item[0]->str_value);
+      if (order->item[0]->with_subselect)
+      {
+        /*
+          Delay the evaluation of constant ORDER and/or GROUP expressions that
+          contain subqueries until the execution phase.
+        */
+        join->exec_const_order_group_cond.push_back(order->item[0]);
+      }
       DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
-      continue;					// skip const item
+      continue;
     }
     else
     {
@@ -11406,7 +11446,7 @@ remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
 	}
       }
     }
-    if (cond->const_item())
+    if (cond->const_item() && !cond->is_expensive())
     {
       *cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
       return (COND*) 0;
@@ -12242,10 +12282,30 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
       {
 	if (thd->is_fatal_error)
 	  goto err;				// Got OOM
-	continue;				// Some kindf of const item
+	continue;				// Some kind of const item
       }
       if (type == Item::SUM_FUNC_ITEM)
-	((Item_sum *) item)->result_field= new_field;
+      {
+        Item_sum *agg_item= (Item_sum *) item;
+        /*
+          Update the result field only if it has never been set, or if the
+          created temporary table is not to be used for subquery
+          materialization.
+
+          The reason is that for subqueries that require materialization as part
+          of their plan, we create the 'external' temporary table needed for IN
+          execution, after the 'internal' temporary table needed for grouping.
+          Since both the external and the internal temporary tables are created
+          for the same list of SELECT fields of the subquery, setting
+          'result_field' for each invocation of create_tmp_table overrides the
+           previous value of 'result_field'.
+
+          The condition below prevents the creation of the external temp table
+          to override the 'result_field' that was set for the internal temp table.
+        */
+        if (!agg_item->result_field || !param->materialized_subquery)
+          agg_item->result_field= new_field;
+      }
       tmp_from_field++;
       reclength+=new_field->pack_length();
       if (!(new_field->flags & NOT_NULL_FLAG))
@@ -15452,7 +15512,6 @@ bool test_if_ref(Item *root_cond, Item_field *left_item,Item *right_item)
 }
 
 
-
 /*
   Extract a condition that can be checked after reading given table
   
@@ -15462,6 +15521,8 @@ bool test_if_ref(Item *root_cond, Item_field *left_item,Item *right_item)
       tables       Tables for which "current field values" are available
       used_table   Table that we're extracting the condition for (may 
                    also include PSEUDO_TABLE_BITS
+      join_tab_idx_arg The index of the JOIN_TAB this Item is being extracted
+                       for. MAX_TABLES if there is no corresponding JOIN_TAB.
       exclude_expensive_cond  Do not push expensive conditions
       retain_ref_cond         Retain ref conditions
 
@@ -15488,34 +15549,27 @@ bool test_if_ref(Item *root_cond, Item_field *left_item,Item *right_item)
 */
 
 static Item *
-make_cond_for_table(Item *cond, table_map tables, table_map used_table,
-                    bool exclude_expensive_cond, bool retain_ref_cond)
+make_cond_for_table(THD *thd, Item *cond, table_map tables,
+                    table_map used_table,
+                    uint join_tab_idx_arg,
+                    bool exclude_expensive_cond __attribute__((unused)),
+		    bool retain_ref_cond)
 {
-  return make_cond_for_table_from_pred(cond, cond, tables, used_table,
+  return make_cond_for_table_from_pred(thd, cond, cond, tables, used_table,
+                                       join_tab_idx_arg,
                                        exclude_expensive_cond,
                                        retain_ref_cond);
 }
-               
+
 static Item *
-make_cond_for_table_from_pred(Item *root_cond, Item *cond,
+make_cond_for_table_from_pred(THD *thd, Item *root_cond, Item *cond,
                               table_map tables, table_map used_table,
-                              bool exclude_expensive_cond,
+                              uint join_tab_idx_arg,
+                              bool exclude_expensive_cond __attribute__((unused)),
                               bool retain_ref_cond)
 
 {
-  if (used_table && !(cond->used_tables() & used_table) &&
-      /*
-        Exclude constant conditions not checked at optimization time if
-        the table we are pushing conditions to is the first one.
-        As a result, such conditions are not considered as already checked
-        and will be checked at execution time, attached to the first table.
-
-        psergey: TODO: "used_table & 1" doesn't make sense in nearly any
-        context. Look at setup_table_map(), table bits reflect the order 
-        the tables were encountered by the parser. Check what we should
-        replace this condition with.
-      */
-      !((used_table & 1) && cond->is_expensive()))
+  if (used_table && !(cond->used_tables() & used_table))
     return (COND*) 0;				// Already checked
   if (cond->type() == Item::COND_ITEM)
   {
@@ -15529,8 +15583,9 @@ make_cond_for_table_from_pred(Item *root_cond, Item *cond,
       Item *item;
       while ((item=li++))
       {
-	Item *fix=make_cond_for_table_from_pred(root_cond, item, 
+	Item *fix=make_cond_for_table_from_pred(thd, root_cond, item, 
                                                 tables, used_table,
+						join_tab_idx_arg,
                                                 exclude_expensive_cond,
                                                 retain_ref_cond);
 	if (fix)
@@ -15543,10 +15598,11 @@ make_cond_for_table_from_pred(Item *root_cond, Item *cond,
 	return new_cond->argument_list()->head();
       default:
 	/*
-	  Item_cond_and do not need fix_fields for execution, its parameters
-	  are fixed or do not need fix_fields, too
+          Call fix_fields to propagate all properties of the children to
+          the new parent Item. This should not be expensive because all
+	  children of Item_cond_and should be fixed by now.
 	*/
-	new_cond->quick_fix_field();
+	new_cond->fix_fields(thd, 0);
 	new_cond->used_tables_cache=
 	  ((Item_cond_and*) cond)->used_tables_cache &
 	  tables;
@@ -15562,8 +15618,9 @@ make_cond_for_table_from_pred(Item *root_cond, Item *cond,
       Item *item;
       while ((item=li++))
       {
-	Item *fix=make_cond_for_table_from_pred(root_cond, item,
+	Item *fix=make_cond_for_table_from_pred(thd, root_cond, item,
                                                 tables, 0L,
+                                                join_tab_idx_arg,
                                                 exclude_expensive_cond,
                                                 retain_ref_cond);
 	if (!fix)
@@ -15571,10 +15628,11 @@ make_cond_for_table_from_pred(Item *root_cond, Item *cond,
 	new_cond->argument_list()->push_back(fix);
       }
       /*
-	Item_cond_and do not need fix_fields for execution, its parameters
-	are fixed or do not need fix_fields, too
+        Call fix_fields to propagate all properties of the children to
+        the new parent Item. This should not be expensive because all
+        children of Item_cond_and should be fixed by now.
       */
-      new_cond->quick_fix_field();
+      new_cond->fix_fields(thd, 0);
       new_cond->used_tables_cache= ((Item_cond_or*) cond)->used_tables_cache;
       new_cond->top_level_item();
       return new_cond;
@@ -15586,16 +15644,14 @@ make_cond_for_table_from_pred(Item *root_cond, Item *cond,
     table_count times, we mark each item that we have examined with the result
     of the test
   */
-  if ((cond->marker == 3 && !retain_ref_cond) || 
-      (cond->used_tables() & ~tables) ||
-      /*
-        When extracting constant conditions, treat expensive conditions as
-        non-constant, so that they are not evaluated at optimization time.
-      */
-      (!used_table && exclude_expensive_cond && cond->is_expensive()))
+  if ((cond->marker == 3 && !retain_ref_cond) ||
+      (cond->used_tables() & ~tables))
     return (COND*) 0;				// Can't check this yet
   if (cond->marker == 2 || cond->eq_cmp_result() == Item::COND_OK)
+  {
+    cond->set_join_tab_idx(join_tab_idx_arg);
     return cond;				// Not boolean op
+  }
 
   if (cond->type() == Item::FUNC_ITEM && 
       ((Item_func*) cond)->functype() == Item_func::EQ_FUNC)
@@ -15616,11 +15672,11 @@ make_cond_for_table_from_pred(Item *root_cond, Item *cond,
     }
   }
   cond->marker=2;
+  cond->set_join_tab_idx(join_tab_idx_arg);
   return cond;
 }
 
 
-
 static COND *
 make_cond_after_sjm(Item *root_cond, Item *cond, table_map tables, 
                     table_map sjm_tables)
@@ -16723,6 +16779,10 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
   table=  tab->table;
   select= tab->select;
 
+  /* Currently ORDER BY ... LIMIT is not supported in subqueries. */
+  DBUG_ASSERT(join->group_list ||
+              !(join->unit->item && join->unit->item->is_in_predicate()));
+
   /*
     When there is SQL_BIG_RESULT do not sort using index for GROUP BY,
     and thus force sorting on disk unless a group min-max optimization
@@ -16834,7 +16894,8 @@ static bool fix_having(JOIN *join, Item **having)
   table_map used_tables= join->const_table_map | table->table->map;
 
   DBUG_EXECUTE("where",print_where(*having,"having", QT_ORDINARY););
-  Item* sort_table_cond=make_cond_for_table(*having, used_tables, used_tables,
+  Item* sort_table_cond= make_cond_for_table(join->thd, *having, used_tables,
+                                            used_tables, MAX_TABLES,
                                             FALSE, FALSE);
   if (sort_table_cond)
   {
@@ -16853,8 +16914,9 @@ static bool fix_having(JOIN *join, Item **having)
     DBUG_EXECUTE("where",print_where(table->select_cond,
 				     "select and having",
                                      QT_ORDINARY););
-    *having= make_cond_for_table(*having,~ (table_map) 0,~used_tables,
-                                 FALSE, FALSE);
+    *having= make_cond_for_table(join->thd, *having,
+                                 ~ (table_map) 0,~used_tables,
+                                 MAX_TABLES, FALSE, FALSE);
     DBUG_EXECUTE("where",
                  print_where(*having,"having after make_cond", QT_ORDINARY););
   }
@@ -19835,28 +19897,9 @@ bool mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
   bool res= 0;
   SELECT_LEX *first= unit->first_select();
 
-  for (SELECT_LEX *sl= first;
-       sl;
-       sl= sl->next_select())
-  {
-    // drop UNCACHEABLE_EXPLAIN, because it is for internal usage only
-    uint8 uncacheable= (sl->uncacheable & ~UNCACHEABLE_EXPLAIN);
-    sl->type= (((&thd->lex->select_lex)==sl)?
-	       (sl->first_inner_unit() || sl->next_select() ? 
-		"PRIMARY" : "SIMPLE"):
-	       ((sl == first)?
-		((sl->linkage == DERIVED_TABLE_TYPE) ?
-		 "DERIVED":
-		 ((uncacheable & UNCACHEABLE_DEPENDENT) ?
-		  "DEPENDENT SUBQUERY":
-		  (uncacheable?"UNCACHEABLE SUBQUERY":
-		   "SUBQUERY"))):
-		((uncacheable & UNCACHEABLE_DEPENDENT) ?
-		 "DEPENDENT UNION":
-		 uncacheable?"UNCACHEABLE UNION":
-		 "UNION")));
-    sl->options|= SELECT_DESCRIBE;
-  }
+  for (SELECT_LEX *sl= first; sl; sl= sl->next_select())
+    sl->set_explain_type();
+
   if (unit->is_union())
   {
     unit->fake_select_lex->select_number= UINT_MAX; // jost for initialization
@@ -20272,6 +20315,8 @@ bool JOIN::change_result(select_result *res)
 {
   DBUG_ENTER("JOIN::change_result");
   result= res;
+  if (tmp_join)
+    tmp_join->result= res;
   if (!procedure && (result->prepare(fields_list, select_lex->master_unit()) ||
                      result->prepare2()))
   {
@@ -20314,6 +20359,155 @@ void JOIN::set_allowed_join_cache_types()
 }
 
 
+/**
+  Save a query execution plan so that the caller can revert to it if needed,
+  and reset the current query plan so that it can be reoptimized.
+
+  @param save_to  The object into which the current query plan state is saved
+*/
+
+void JOIN::save_query_plan(Query_plan_state *save_to)
+{
+  if (keyuse.elements)
+  {
+    DYNAMIC_ARRAY tmp_keyuse;
+    /* Swap the current and the backup keyuse internal arrays. */
+    tmp_keyuse= keyuse;
+    keyuse= save_to->keyuse; /* keyuse is reset to an empty array. */
+    save_to->keyuse= tmp_keyuse;
+
+    for (uint i= 0; i < tables; i++)
+    {
+      save_to->join_tab_keyuse[i]= join_tab[i].keyuse;
+      join_tab[i].keyuse= NULL;
+      save_to->join_tab_checked_keys[i]= join_tab[i].checked_keys;
+      join_tab[i].checked_keys.clear_all();
+    }
+  }
+  memcpy((uchar*) save_to->best_positions, (uchar*) best_positions,
+         sizeof(POSITION) * (tables + 1));
+  memset(best_positions, 0, sizeof(POSITION) * (tables + 1));
+}
+
+
+/**
+  Restore a query execution plan previously saved by the caller.
+
+  @param The object from which the current query plan state is restored.
+*/
+
+void JOIN::restore_query_plan(Query_plan_state *restore_from)
+{
+  if (restore_from->keyuse.elements)
+  {
+    DYNAMIC_ARRAY tmp_keyuse;
+    tmp_keyuse= keyuse;
+    keyuse= restore_from->keyuse;
+    restore_from->keyuse= tmp_keyuse;
+
+    for (uint i= 0; i < tables; i++)
+    {
+      join_tab[i].keyuse= restore_from->join_tab_keyuse[i];
+      join_tab[i].checked_keys= restore_from->join_tab_checked_keys[i];
+    }
+
+  }
+  memcpy((uchar*) best_positions, (uchar*) restore_from->best_positions,
+         sizeof(POSITION) * (tables + 1));
+}
+
+
+/**
+  Reoptimize a query plan taking into account an additional conjunct to the
+  WHERE clause.
+
+  @param added_where  An extra conjunct to the WHERE clause to reoptimize with
+  @param join_tables  The set of tables to reoptimize
+  @param save_to      If != NULL, save here the state of the current query plan
+
+  @notes
+  Given a query plan that was already optimized taking into account some WHERE
+  clause 'C', reoptimize this plan with a new WHERE clause 'C AND added_where'.
+  The reoptimization works as follows:
+
+  1. Call update_ref_and_keys *only* for the new conditions 'added_where'
+     that are about to be injected into the query.
+  2. Expand if necessary the original KEYUSE array JOIN::keyuse to
+     accommodate the new REF accesses computed for the 'added_where' condition.
+  3. Add the new KEYUSEs into JOIN::keyuse.
+  4. Re-sort and re-filter the JOIN::keyuse array with the newly added
+     KEYUSE elements. 
+ 
+  @retval REOPT_NEW_PLAN  there is a new plan.
+  @retval REOPT_OLD_PLAN  no new improved plan was produced, use the old one.
+  @retval REOPT_ERROR     an irrecovarable error occured during reoptimization.
+*/
+
+JOIN::enum_reopt_result
+JOIN::reoptimize(Item *added_where, table_map join_tables,
+                 Query_plan_state *save_to)
+{
+  DYNAMIC_ARRAY added_keyuse;
+  SARGABLE_PARAM *sargables= 0; /* Used only as a dummy parameter. */
+  uint org_keyuse_elements;
+
+  /* Re-run the REF optimizer to take into account the new conditions. */
+  if (update_ref_and_keys(thd, &added_keyuse, join_tab, tables, added_where,
+                          ~outer_join, select_lex, &sargables))
+  {
+    delete_dynamic(&added_keyuse);
+    return REOPT_ERROR;
+  }
+
+  if (!added_keyuse.elements)
+  {
+    delete_dynamic(&added_keyuse);
+    return REOPT_OLD_PLAN;
+  }
+
+  if (save_to)
+    save_query_plan(save_to);
+
+  if (!keyuse.buffer &&
+      my_init_dynamic_array(&keyuse, sizeof(KEYUSE), 20, 64))
+  {
+    delete_dynamic(&added_keyuse);
+    return REOPT_ERROR;
+  }
+
+  org_keyuse_elements= save_to ? save_to->keyuse.elements : keyuse.elements;
+  allocate_dynamic(&keyuse, org_keyuse_elements + added_keyuse.elements);
+
+  /* If needed, add the access methods from the original query plan. */
+  if (save_to)
+  {
+    DBUG_ASSERT(!keyuse.elements);
+    memcpy(keyuse.buffer,
+           save_to->keyuse.buffer,
+           (size_t) save_to->keyuse.elements * keyuse.size_of_element);
+    keyuse.elements= save_to->keyuse.elements;
+  }
+
+  /* Add the new access methods to the keyuse array. */
+  memcpy(keyuse.buffer + keyuse.elements * keyuse.size_of_element,
+         added_keyuse.buffer,
+         (size_t) added_keyuse.elements * added_keyuse.size_of_element);
+  keyuse.elements+= added_keyuse.elements;
+  /* added_keyuse contents is copied, and it is no longer needed. */
+  delete_dynamic(&added_keyuse);
+
+  if (sort_and_filter_keyuse(&keyuse))
+    return REOPT_ERROR;
+  optimize_keyuse(this, &keyuse);
+
+  /* Re-run the join optimizer to compute a new query plan. */
+  if (choose_plan(this, join_tables))
+    return REOPT_ERROR;
+
+  return REOPT_NEW_PLAN;
+}
+
+
 /**
   @} (end of group Query_Optimizer)
 */
diff --git a/sql/sql_select.h b/sql/sql_select.h
index f0eda9671cb..5de7620c7d8 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -603,8 +603,53 @@ inline bool sj_is_materialize_strategy(uint strategy)
 
 class JOIN :public Sql_alloc
 {
+private:
   JOIN(const JOIN &rhs);                        /**< not implemented */
   JOIN& operator=(const JOIN &rhs);             /**< not implemented */
+
+protected:
+
+  /**
+    The subset of the state of a JOIN that represents an optimized query
+    execution plan. Allows saving/restoring different plans for the same query.
+  */
+  class Query_plan_state {
+  public:
+    DYNAMIC_ARRAY keyuse; /* Copy of the JOIN::keyuse array. */
+    POSITION best_positions[MAX_TABLES+1]; /* Copy of JOIN::best_positions */
+    /* Copies of the JOIN_TAB::keyuse pointers for each JOIN_TAB. */
+    KEYUSE *join_tab_keyuse[MAX_TABLES];
+    /* Copies of JOIN_TAB::checked_keys for each JOIN_TAB. */
+    key_map join_tab_checked_keys[MAX_TABLES];
+  public:
+    Query_plan_state()
+    {   
+      keyuse.elements= 0;
+      keyuse.buffer= NULL;
+    }
+    Query_plan_state(JOIN *join);
+    ~Query_plan_state()
+    {
+      delete_dynamic(&keyuse);
+    }
+  };
+
+  /* Results of reoptimizing a JOIN via JOIN::reoptimize(). */
+  enum enum_reopt_result {
+    REOPT_NEW_PLAN, /* there is a new reoptimized plan */
+    REOPT_OLD_PLAN, /* no new improved plan can be found, use the old one */
+    REOPT_ERROR,    /* an irrecovarable error occured during reoptimization */
+    REOPT_NONE      /* not yet reoptimized */
+  };
+
+  /* Support for plan reoptimization with rewritten conditions. */
+  enum_reopt_result reoptimize(Item *added_where, table_map join_tables,
+                               Query_plan_state *save_to);
+  void save_query_plan(Query_plan_state *save_to);
+  void restore_query_plan(Query_plan_state *restore_from);
+  /* Choose a subquery plan for a table-less subquery. */
+  bool choose_tableless_subquery_plan();
+
 public:
   JOIN_TAB *join_tab,**best_ref;
   JOIN_TAB **map2table;    ///< mapping between table indexes and JOIN_TABs
@@ -702,6 +747,13 @@ public:
     account the changes made by test_if_skip_sort_order()).
   */
   double   best_read;
+  /*
+    Estimated result rows (fanout) of the whole query. If this is a subquery
+    that is reexecuted multiple times, this value includes the estiamted # of
+    reexecutions. This value is equal to the multiplication of all
+    join->positions[i].records_read of a JOIN.
+  */
+  double   record_count;
   List<Item> *fields;
   List<Cached_item> group_fields, group_fields_cache;
   TABLE    *tmp_table;
@@ -815,6 +867,19 @@ public:
   List<TABLE_LIST> *join_list;       ///< list of joined tables in reverse order
   COND_EQUAL *cond_equal;
   COND_EQUAL *having_equal;
+  /*
+    Constant codition computed during optimization, but evaluated during
+    join execution. Typically expensive conditions that should not be
+    evaluated at optimization time.
+  */
+  Item *exec_const_cond;
+  /*
+    Constant ORDER and/or GROUP expressions that contain subqueries. Such
+    expressions need to evaluated to verify that the subquery indeed
+    returns a single row. The evaluation of such expressions is delayed
+    until query execution.
+  */
+  List<Item> exec_const_order_group_cond;
   SQL_SELECT *select;                ///<created in optimisation phase
   JOIN_TAB *return_tab;              ///<used only for outer joins
   Item **ref_pointer_array; ///<used pointer reference for this select
@@ -825,8 +890,15 @@ public:
   
   bool union_part; ///< this subselect is part of union 
   bool optimized; ///< flag to avoid double optimization in EXPLAIN
+  bool initialized; ///< flag to avoid double init_execution calls
 
   Array<Item_in_subselect> sj_subselects;
+  /*
+    Additional WHERE and HAVING predicates to be considered for IN=>EXISTS
+    subquery transformation of a JOIN object.
+  */
+  Item *in_to_exists_where;
+  Item *in_to_exists_having;
 
   /* Temporary tables used to weed-out semi-join duplicates */
   List<TABLE> sj_tmp_tables;
@@ -901,8 +973,10 @@ public:
     ref_pointer_array_size= 0;
     zero_result_cause= 0;
     optimized= 0;
+    initialized= 0;
     cond_equal= 0;
     having_equal= 0;
+    exec_const_cond= 0;
     group_optimized_away= 0;
     no_rows_in_result_called= 0;
 
@@ -917,6 +991,8 @@ public:
     no_const_tables= FALSE;
     first_select= sub_select;
     outer_ref_cond= 0;
+    in_to_exists_where= NULL;
+    in_to_exists_having= NULL;
   }
 
   int prepare(Item ***rref_pointer_array, TABLE_LIST *tables, uint wind_num,
@@ -925,12 +1001,13 @@ public:
 	      SELECT_LEX_UNIT *unit);
   int optimize();
   int reinit();
+  int init_execution();
   void exec();
   int destroy();
   void restore_tmp();
   bool alloc_func_list();
   bool flatten_subqueries();
-  bool setup_subquery_materialization();
+  bool optimize_unflattened_subqueries();
   bool make_sum_func_list(List<Item> &all_fields, List<Item> &send_fields,
 			  bool before_group_by, bool recompute= FALSE);
 
@@ -966,7 +1043,7 @@ public:
   bool init_save_join_tab();
   bool send_row_on_empty_set()
   {
-    return (do_send_rows && implicit_grouping &&
+    return (do_send_rows && implicit_grouping && !group_optimized_away &&
             having_value != Item::COND_FALSE);
   }
   bool change_result(select_result *result);
@@ -999,6 +1076,9 @@ public:
     return test(allowed_join_cache_types & JOIN_CACHE_HASHED_BIT) &&
            max_allowed_join_cache_level > JOIN_CACHE_HASHED_BIT;
   }
+  bool choose_subquery_plan(table_map join_tables);
+  void get_partial_join_cost(uint n_tables,
+                             double *read_time_arg, double *record_count_arg);
 
 private:
   /**
@@ -1233,6 +1313,9 @@ protected:
     if (!inited)
     {
       inited=1;
+      TABLE *table= to_field->table;
+      my_bitmap_map *old_map= dbug_tmp_use_all_columns(table,
+                                                       table->write_set);
       if ((res= item->save_in_field(to_field, 1)))
       {       
         if (!err)
@@ -1244,6 +1327,7 @@ protected:
         */
       if (!err && to_field->table->in_use->is_error())
         err= 1; /* STORE_KEY_FATAL */
+      dbug_tmp_restore_column_map(table->write_set, old_map);
     }
     null_key= to_field->is_null() || item->null_value;
     return (err > 2 ? STORE_KEY_FATAL : (store_key_result) err);
@@ -1262,9 +1346,7 @@ inline Item * and_items(Item* cond, Item *item)
 {
   return (cond? (new Item_cond_and(cond, item)) : item);
 }
-bool choose_plan(JOIN *join,table_map join_tables);
-void get_partial_join_cost(JOIN *join, uint n_tables, double *read_time_arg,
-                           double *record_count_arg);
+bool choose_plan(JOIN *join, table_map join_tables);
 void optimize_wo_join_buffering(JOIN *join, uint first_tab, uint last_tab, 
                                 table_map last_remaining_tables, 
                                 bool first_alt, uint no_jbuf_before,
@@ -1309,5 +1391,6 @@ bool create_internal_tmp_table(TABLE *table, KEY *keyinfo,
                                ulonglong options);
 bool open_tmp_table(TABLE *table);
 void setup_tmp_table_column_bitmaps(TABLE *table, uchar *bitmaps);
+double prev_record_reads(POSITION *positions, uint idx, table_map found_ref);
 
 #endif /* SQL_SELECT_INCLUDED */
diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index a94ad9f3b4b..4a6c37f5f80 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -184,6 +184,8 @@ st_select_lex_unit::init_prepare_fake_select_lex(THD *thd_arg)
   {
     (*order->item)->walk(&Item::change_context_processor, 0,
                          (uchar*) &fake_select_lex->context);
+    (*order->item)->walk(&Item::set_fake_select_as_master_processor, 0,
+                         (uchar*) fake_select_lex);
   }
 }
 
@@ -268,6 +270,18 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
 
     can_skip_order_by= is_union_select && !(sl->braces && sl->explicit_limit);
 
+    /*
+      Remove all references from the select_lex_units to the subqueries that
+      are inside the ORDER BY clause.
+    */
+    if (can_skip_order_by)
+    {
+      for (ORDER *ord= (ORDER *)sl->order_list.first; ord; ord= ord->next)
+      {
+        (*ord->item)->walk(&Item::eliminate_subselect_processor, FALSE, NULL);
+      }
+    }
+
     saved_error= join->prepare(&sl->ref_pointer_array,
                                sl->table_list.first,
                                sl->with_wild,
diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index 0a4d3a4ba80..7e40e3516f6 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -307,6 +307,10 @@ int mysql_update(THD *thd,
     DBUG_RETURN(1);				/* purecov: inspected */
   }
 
+  /* Apply the IN=>EXISTS transformation to all subqueries and optimize them. */
+  if (select_lex->optimize_unflattened_subqueries())
+    DBUG_RETURN(TRUE);
+
   if (select_lex->inner_refs_list.elements &&
     fix_inner_refs(thd, all_fields, select_lex, select_lex->ref_pointer_array))
     DBUG_RETURN(1);