From 9947636bbaede8996ac81b37f84c779c7fadd5df Mon Sep 17 00:00:00 2001
From: Georgi Kodinov <joro@sun.com>
Date: Fri, 12 Feb 2010 18:28:35 +0200
Subject: [PATCH 1/6] Bug #35250: readline check breaks when doing vpath build

Fixed several (obvious) places that don't work with vpath
build.
---
 configure.in                            | 2 +-
 mysql-test/Makefile.am                  | 4 ++--
 scripts/Makefile.am                     | 5 +++--
 sql/share/Makefile.am                   | 8 ++++----
 storage/ndb/src/common/util/Makefile.am | 2 +-
 5 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/configure.in b/configure.in
index 88e0ebf1faa..45f86677a86 100644
--- a/configure.in
+++ b/configure.in
@@ -2711,7 +2711,7 @@ case $SYSTEM_TYPE in
     fi
 
     # if there is no readline, but we want to build with readline, we fail
-    if [test "$want_to_use_readline" = "yes"] && [test ! -d "./cmd-line-utils/readline"]
+    if [test "$want_to_use_readline" = "yes"] && [test ! -d "$srcdir/cmd-line-utils/readline"]
     then
 	AC_MSG_ERROR([This commercially licensed MySQL source package can't
 	      be built with libreadline. Please use --with-libedit to use
diff --git a/mysql-test/Makefile.am b/mysql-test/Makefile.am
index b1d0e85c70e..31770592d53 100644
--- a/mysql-test/Makefile.am
+++ b/mysql-test/Makefile.am
@@ -130,12 +130,12 @@ uninstall-local:
 # mtr - a shortcut for executing mysql-test-run.pl
 mtr:
 	$(RM) -f mtr
-	$(LN_S) mysql-test-run.pl mtr
+	$(LN_S) $(srcdir)/mysql-test-run.pl mtr
 
 # mysql-test-run - a shortcut for executing mysql-test-run.pl
 mysql-test-run:
 	$(RM) -f mysql-test-run
-	$(LN_S) mysql-test-run.pl mysql-test-run
+	$(LN_S) $(srcdir)/mysql-test-run.pl mysql-test-run
 
 # Don't update the files from bitkeeper
 %::SCCS/s.%
diff --git a/scripts/Makefile.am b/scripts/Makefile.am
index 0292617c7a5..1aa24c5d432 100644
--- a/scripts/Makefile.am
+++ b/scripts/Makefile.am
@@ -110,7 +110,8 @@ mysqlbug: ${top_builddir}/config.status mysqlbug.sh
 mysql_fix_privilege_tables.sql: mysql_system_tables.sql \
 				mysql_system_tables_fix.sql
 	@echo "Building $@";
-	@cat mysql_system_tables.sql mysql_system_tables_fix.sql > $@
+	@cat $(srcdir)/mysql_system_tables.sql \
+	  $(srcdir)/mysql_system_tables_fix.sql > $@
 
 #
 # Build mysql_fix_privilege_tables_sql.c from
@@ -123,7 +124,7 @@ mysql_fix_privilege_tables_sql.c: comp_sql.c mysql_fix_privilege_tables.sql
 	sleep 2
 	$(top_builddir)/scripts/comp_sql$(EXEEXT) \
 	  mysql_fix_privilege_tables \
-	    $(top_srcdir)/scripts/mysql_fix_privilege_tables.sql $@
+	    $(top_builddir)/scripts/mysql_fix_privilege_tables.sql $@
 
 
 SUFFIXES = .sh
diff --git a/sql/share/Makefile.am b/sql/share/Makefile.am
index 68b393e619f..357f9ac0876 100644
--- a/sql/share/Makefile.am
+++ b/sql/share/Makefile.am
@@ -22,7 +22,7 @@ dist-hook:
 	  test -d $(distdir)/$$dir || mkdir $(distdir)/$$dir; \
 	  $(INSTALL_DATA) $(srcdir)/$$dir/*.* $(distdir)/$$dir; \
 	done; \
-	sleep 1 ; touch $(srcdir)/*/errmsg.sys
+	sleep 1 ; touch $(builddir)/*/errmsg.sys
 	$(INSTALL_DATA) $(srcdir)/charsets/README $(distdir)/charsets
 	$(INSTALL_DATA) $(srcdir)/charsets/Index.xml $(distdir)/charsets
 
@@ -39,11 +39,11 @@ install-data-local:
 	for lang in @AVAILABLE_LANGUAGES@; \
 	do \
 		$(mkinstalldirs) $(DESTDIR)$(pkgdatadir)/$$lang; \
-		$(INSTALL_DATA) $(srcdir)/$$lang/errmsg.sys \
+		$(INSTALL_DATA) $(builddir)/$$lang/errmsg.sys \
 			        $(DESTDIR)$(pkgdatadir)/$$lang/errmsg.sys; \
 	done
 	$(mkinstalldirs) $(DESTDIR)$(pkgdatadir)/charsets
-		$(INSTALL_DATA) $(srcdir)/errmsg.txt \
+		$(INSTALL_DATA) $(builddir)/errmsg.txt \
 	        $(DESTDIR)$(pkgdatadir)/errmsg.txt; \
 	$(INSTALL_DATA) $(srcdir)/charsets/README $(DESTDIR)$(pkgdatadir)/charsets/README
 	$(INSTALL_DATA) $(srcdir)/charsets/*.xml $(DESTDIR)$(pkgdatadir)/charsets
@@ -53,7 +53,7 @@ uninstall-local:
 	@RM@ -f -r $(DESTDIR)$(pkgdatadir)
 
 distclean-local:
-	@RM@ -f */errmsg.sys
+	@RM@ -f $(builddir)/*/errmsg.sys
 
 # Do nothing
 link_sources:
diff --git a/storage/ndb/src/common/util/Makefile.am b/storage/ndb/src/common/util/Makefile.am
index 5379a425c49..5cf02fed12f 100644
--- a/storage/ndb/src/common/util/Makefile.am
+++ b/storage/ndb/src/common/util/Makefile.am
@@ -37,7 +37,7 @@ testBitmask_LDFLAGS = @ndb_bin_am_ldflags@ \
 
 testBitmask.cpp : Bitmask.cpp
 	rm -f testBitmask.cpp
-	@LN_CP_F@ Bitmask.cpp testBitmask.cpp
+	@LN_CP_F@ $(srcdir)/Bitmask.cpp testBitmask.cpp
 
 testBitmask.o:	$(testBitmask_SOURCES)
 		$(CXXCOMPILE) -c $(INCLUDES) -D__TEST_BITMASK__ $<

From b5ae1327f73af7e893bf6415a74d633739fa903b Mon Sep 17 00:00:00 2001
From: Georgi Kodinov <joro@sun.com>
Date: Thu, 25 Feb 2010 16:57:15 +0200
Subject: [PATCH 2/6] Backport of the fix for bug #49552 to 5.0-bugteam

---
 mysql-test/r/delete.result | 12 ++++++++++++
 mysql-test/t/delete.test   | 15 +++++++++++++++
 sql/sql_parse.cc           |  4 ++--
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/mysql-test/r/delete.result b/mysql-test/r/delete.result
index a682d90fbf7..d3cf69279fd 100644
--- a/mysql-test/r/delete.result
+++ b/mysql-test/r/delete.result
@@ -241,4 +241,16 @@ DELETE FROM t1 ORDER BY (f1(10)) LIMIT 1;
 ERROR 42000: Incorrect number of arguments for FUNCTION test.f1; expected 0, got 1
 DROP TABLE t1;
 DROP FUNCTION f1;
+#
+# Bug #49552 : sql_buffer_result cause crash + not found records 
+#   in multitable delete/subquery
+#
+CREATE TABLE t1(a INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+SET SESSION SQL_BUFFER_RESULT=1;
+DELETE t1 FROM (SELECT SUM(a) a FROM t1) x,t1;
+SET SESSION SQL_BUFFER_RESULT=DEFAULT;
+SELECT * FROM t1;
+a
+DROP TABLE t1;
 End of 5.0 tests
diff --git a/mysql-test/t/delete.test b/mysql-test/t/delete.test
index ec70587c9d1..d9091c92a52 100644
--- a/mysql-test/t/delete.test
+++ b/mysql-test/t/delete.test
@@ -247,4 +247,19 @@ DELETE FROM t1 ORDER BY (f1(10)) LIMIT 1;
 DROP TABLE t1;
 DROP FUNCTION f1;
 
+
+--echo #
+--echo # Bug #49552 : sql_buffer_result cause crash + not found records 
+--echo #   in multitable delete/subquery
+--echo #
+
+CREATE TABLE t1(a INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+SET SESSION SQL_BUFFER_RESULT=1;
+DELETE t1 FROM (SELECT SUM(a) a FROM t1) x,t1;
+
+SET SESSION SQL_BUFFER_RESULT=DEFAULT;
+SELECT * FROM t1;
+DROP TABLE t1;
+
 --echo End of 5.0 tests
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 61c2d70a563..64d6888d772 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -4009,9 +4009,9 @@ end_with_restore_list:
 			select_lex->where,
 			0, (ORDER *)NULL, (ORDER *)NULL, (Item *)NULL,
 			(ORDER *)NULL,
-			select_lex->options | thd->options |
+			(select_lex->options | thd->options |
 			SELECT_NO_JOIN_CACHE | SELECT_NO_UNLOCK |
-                        OPTION_SETUP_TABLES_DONE,
+                        OPTION_SETUP_TABLES_DONE) & ~OPTION_BUFFER_RESULT,
 			del_result, unit, select_lex);
       res|= thd->net.report_error;
       if (unlikely(res))

From 735de9ea7e3f16ac53c413a19e772b19e2bc8dd8 Mon Sep 17 00:00:00 2001
From: Alexey Kopytov <Alexey.Kopytov@Sun.com>
Date: Thu, 25 Feb 2010 18:48:53 +0300
Subject: [PATCH 3/6] Bug #50335: Assertion `!(order->used & map)' in
 eq_ref_table

The problem was in an incorrect debug assertion. The expression
used in the failing assertion states that when finding
references matching ORDER BY expressions, there can be only one
reference to a single table. But that does not make any sense,
all test cases for this bug are valid examples with multiple
identical WHERE expressions referencing the same table which
are also present in the ORDER BY list.

Fixed by removing the failing assertion. We also have to take
care of the 'found' counter so that we count multiple
references only once. We rely on this fact later in
eq_ref_table().
---
 mysql-test/r/join.result | 11 +++++++++++
 mysql-test/t/join.test   | 13 +++++++++++++
 sql/sql_select.cc        |  8 +++++---
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/mysql-test/r/join.result b/mysql-test/r/join.result
index 8691eb27220..102b39c3992 100644
--- a/mysql-test/r/join.result
+++ b/mysql-test/r/join.result
@@ -1145,3 +1145,14 @@ NULL
 NULL
 1
 DROP TABLE t1, t2, mm1;
+#
+# Bug #50335: Assertion `!(order->used & map)' in eq_ref_table
+# 
+CREATE TABLE t1 (a INT NOT NULL, b INT NOT NULL, PRIMARY KEY (a,b));
+INSERT INTO t1 VALUES (0,0), (1,1);
+SELECT * FROM t1 STRAIGHT_JOIN t1 t2 ON t1.a=t2.a AND t1.a=t2.b ORDER BY t2.a, t1.a;
+a	b	a	b
+0	0	0	0
+1	1	1	1
+DROP TABLE t1;
+End of 5.1 tests
diff --git a/mysql-test/t/join.test b/mysql-test/t/join.test
index 645321a3a5e..761121313e5 100644
--- a/mysql-test/t/join.test
+++ b/mysql-test/t/join.test
@@ -816,3 +816,16 @@ CREATE TABLE mm1(a CHAR(9),b INT,KEY(b),KEY(a))
 ENGINE=MERGE  UNION=(t1,t2);
 SELECT t1.a FROM mm1,t1;
 DROP TABLE t1, t2, mm1;
+
+--echo #
+--echo # Bug #50335: Assertion `!(order->used & map)' in eq_ref_table
+--echo # 
+
+CREATE TABLE t1 (a INT NOT NULL, b INT NOT NULL, PRIMARY KEY (a,b));
+INSERT INTO t1 VALUES (0,0), (1,1);
+
+SELECT * FROM t1 STRAIGHT_JOIN t1 t2 ON t1.a=t2.a AND t1.a=t2.b ORDER BY t2.a, t1.a;
+
+DROP TABLE t1;
+
+--echo End of 5.1 tests
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 52f9aae7a0c..b9f59fac4d6 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -7028,9 +7028,11 @@ eq_ref_table(JOIN *join, ORDER *start_order, JOIN_TAB *tab)
       }
       if (order)
       {
-	found++;
-	DBUG_ASSERT(!(order->used & map));
-	order->used|=map;
+        if (!(order->used & map))
+        {
+          found++;
+          order->used|= map;
+        }
 	continue;				// Used in ORDER BY
       }
       if (!only_eq_ref_tables(join,start_order, (*ref_item)->used_tables()))

From 79d8de67a911be0f18adfd4c19c65909879b76eb Mon Sep 17 00:00:00 2001
From: Gleb Shchepa <gshchepa@mysql.com>
Date: Thu, 25 Feb 2010 23:13:11 +0400
Subject: [PATCH 4/6] Bug #45360: wrong results

Propagation of a large unsigned numeric constant
in the WHERE expression led to wrong result.

For example,
"WHERE a = CAST(0xFFFFFFFFFFFFFFFF AS USIGNED) AND FOO(a)",
where a is an UNSIGNED BIGINT, and FOO() accepts strings,
was transformed to "... AND FOO('-1')".

That has been fixed.

Also EXPLAIN EXTENDED printed incorrect numeric constants in
transformed WHERE expressions like above. That has been
fixed too.
---
 mysql-test/r/bigint.result | 34 ++++++++++++++++++++++++++++++++++
 mysql-test/t/bigint.test   | 35 +++++++++++++++++++++++++++++++++++
 sql/item.cc                |  4 ++--
 3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/mysql-test/r/bigint.result b/mysql-test/r/bigint.result
index 4a5b8fcf4aa..8f9b75fc664 100644
--- a/mysql-test/r/bigint.result
+++ b/mysql-test/r/bigint.result
@@ -404,3 +404,37 @@ describe t1;
 Field	Type	Null	Key	Default	Extra
 bi	decimal(19,0)	NO		0	
 drop table t1;
+#
+# Bug #45360: wrong results
+#
+CREATE TABLE t1 (id INT AUTO_INCREMENT PRIMARY KEY,
+a BIGINT(20) UNSIGNED,
+b VARCHAR(20));
+INSERT INTO t1 (a) VALUES
+(0),
+(CAST(0x7FFFFFFFFFFFFFFF AS UNSIGNED)),
+(CAST(0x8000000000000000 AS UNSIGNED)),
+(CAST(0xFFFFFFFFFFFFFFFF AS UNSIGNED));
+UPDATE t1 SET b = a;
+# FFFFFFFFFFFFFFFF
+EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE a = 18446744073709551615 AND TRIM(a) = b;
+SHOW WARNINGS;
+Level	Code	Message
+Note	1003	select 1 AS `1` from `test`.`t1` where ((`test`.`t1`.`a` = 18446744073709551615) and ('18446744073709551615' = `test`.`t1`.`b`))
+# 8000000000000000
+EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE a = 9223372036854775808 AND TRIM(a) = b;
+SHOW WARNINGS;
+Level	Code	Message
+Note	1003	select 1 AS `1` from `test`.`t1` where ((`test`.`t1`.`a` = 9223372036854775808) and ('9223372036854775808' = `test`.`t1`.`b`))
+# 7FFFFFFFFFFFFFFF
+EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE a = 9223372036854775807 AND TRIM(a) = b;
+SHOW WARNINGS;
+Level	Code	Message
+Note	1003	select 1 AS `1` from `test`.`t1` where ((`test`.`t1`.`a` = 9223372036854775807) and ('9223372036854775807' = `test`.`t1`.`b`))
+# 0
+EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE a = 0 AND TRIM(a) = b;
+SHOW WARNINGS;
+Level	Code	Message
+Note	1003	select 1 AS `1` from `test`.`t1` where ((`test`.`t1`.`a` = 0) and ('0' = `test`.`t1`.`b`))
+DROP TABLE t1;
+# End of 5.1 tests
diff --git a/mysql-test/t/bigint.test b/mysql-test/t/bigint.test
index 5a589816dcd..e19bba971f9 100644
--- a/mysql-test/t/bigint.test
+++ b/mysql-test/t/bigint.test
@@ -327,3 +327,38 @@ drop table t1;
 create table t1 select -9223372036854775809 bi;
 describe t1;
 drop table t1;
+
+--echo #
+--echo # Bug #45360: wrong results
+--echo #
+
+CREATE TABLE t1 (id INT AUTO_INCREMENT PRIMARY KEY,
+                 a BIGINT(20) UNSIGNED,
+                 b VARCHAR(20));
+
+INSERT INTO t1 (a) VALUES
+  (0),
+  (CAST(0x7FFFFFFFFFFFFFFF AS UNSIGNED)),
+  (CAST(0x8000000000000000 AS UNSIGNED)),
+  (CAST(0xFFFFFFFFFFFFFFFF AS UNSIGNED));
+
+UPDATE t1 SET b = a;
+
+let $n = `SELECT MAX(id) FROM t1`;
+while($n) {
+  let $x = `SELECT a FROM t1 WHERE id = $n`;
+  dec $n;
+  let $hex = `SELECT HEX($x)`;
+  echo # $hex;
+
+  --disable_result_log
+  eval EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE a = $x AND TRIM(a) = b;
+  --enable_result_log
+  SHOW WARNINGS;
+}
+
+DROP TABLE t1;
+
+--echo # End of 5.1 tests
+
+
diff --git a/sql/item.cc b/sql/item.cc
index f8cca3a0667..934e897f923 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -2209,14 +2209,14 @@ String *Item_int::val_str(String *str)
 {
   // following assert is redundant, because fixed=1 assigned in constructor
   DBUG_ASSERT(fixed == 1);
-  str->set(value, &my_charset_bin);
+  str->set_int(value, unsigned_flag, &my_charset_bin);
   return str;
 }
 
 void Item_int::print(String *str, enum_query_type query_type)
 {
   // my_charset_bin is good enough for numbers
-  str_value.set(value, &my_charset_bin);
+  str_value.set_int(value, unsigned_flag, &my_charset_bin);
   str->append(str_value);
 }
 

From cc01fc3f5f1860670113f10a1ac968a8067ab071 Mon Sep 17 00:00:00 2001
From: Evgeny Potemkin <epotemkin@mysql.com>
Date: Fri, 26 Feb 2010 14:17:00 +0300
Subject: [PATCH 5/6] Bug#50843: Filesort used instead of clustered index led
 to performance degradation.

Filesort + join cache combination is preferred to full index scan because it
is usually faster. But it's not the case when the index is clustered one.

Now test_if_skip_sort_order function prefers filesort only if index isn't
clustered.
---
 mysql-test/r/innodb_mysql.result | 14 ++++++++++++++
 mysql-test/t/innodb_mysql.test   | 12 ++++++++++++
 sql/sql_select.cc                | 19 +++++++++++++------
 3 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/mysql-test/r/innodb_mysql.result b/mysql-test/r/innodb_mysql.result
index b54fb90b412..c4279018cb8 100644
--- a/mysql-test/r/innodb_mysql.result
+++ b/mysql-test/r/innodb_mysql.result
@@ -2281,4 +2281,18 @@ CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=innodb ;
 SELECT 1 FROM t1 JOIN t1 a USING(a) GROUP BY t1.a,t1.a;
 1
 DROP TABLE t1;
+#
+# Bug#50843: Filesort used instead of clustered index led to
+#            performance degradation.
+#
+create table t1(f1 int not null primary key, f2 int) engine=innodb;
+create table t2(f1 int not null, key (f1)) engine=innodb;
+insert into t1 values (1,1),(2,2),(3,3);
+insert into t2 values (1),(2),(3);
+explain select t1.* from t1 left join t2 using(f1) group by t1.f1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	3	
+1	SIMPLE	t2	ref	f1	f1	4	test.t1.f1	1	Using index
+drop table t1,t2;
+#
 End of 5.1 tests
diff --git a/mysql-test/t/innodb_mysql.test b/mysql-test/t/innodb_mysql.test
index d9fecccfbdc..a3c11b8b8d6 100644
--- a/mysql-test/t/innodb_mysql.test
+++ b/mysql-test/t/innodb_mysql.test
@@ -545,5 +545,17 @@ CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=innodb ;
 SELECT 1 FROM t1 JOIN t1 a USING(a) GROUP BY t1.a,t1.a;
 DROP TABLE t1;
 
+--echo #
+--echo # Bug#50843: Filesort used instead of clustered index led to
+--echo #            performance degradation.
+--echo #
+create table t1(f1 int not null primary key, f2 int) engine=innodb;
+create table t2(f1 int not null, key (f1)) engine=innodb;
+insert into t1 values (1,1),(2,2),(3,3);
+insert into t2 values (1),(2),(3);
+explain select t1.* from t1 left join t2 using(f1) group by t1.f1;
+drop table t1,t2;
+--echo #
+
 
 --echo End of 5.1 tests
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 52f9aae7a0c..c4fac5b50ef 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -13304,12 +13304,6 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
     */
     if (select_limit >= table_records)
     {
-      /* 
-        filesort() and join cache are usually faster than reading in 
-        index order and not using join cache
-        */
-      if (tab->type == JT_ALL && tab->join->tables > tab->join->const_tables + 1)
-        DBUG_RETURN(0);
       keys= *table->file->keys_to_use_for_scanning();
       keys.merge(table->covering_keys);
 
@@ -13459,6 +13453,19 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
 	}      
       }
     }
+
+    /*
+      filesort() and join cache are usually faster than reading in 
+      index order and not using join cache, except in case that chosen
+      index is clustered primary key.
+    */
+    if ((select_limit >= table_records) &&
+        (tab->type == JT_ALL &&
+         tab->join->tables > tab->join->const_tables + 1) &&
+         ((unsigned) best_key != table->s->primary_key ||
+          !table->file->primary_key_is_clustered()))
+      DBUG_RETURN(0);
+
     if (best_key >= 0)
     {
       bool quick_created= FALSE;

From fe94dec6799b81ddc6660b3d9301deff5ac82507 Mon Sep 17 00:00:00 2001
From: Sergey Glukhov <Sergey.Glukhov@sun.com>
Date: Fri, 26 Feb 2010 15:39:25 +0400
Subject: [PATCH 6/6] Bug#50995 Having clause on subquery result produces
 incorrect results. The problem is that cond->fix_fields(thd, 0) breaks
 condition(cuts off 'having'). The reason of that is that NULL valued Item
 pointer is present in the middle of Item list and it breaks the Item
 processing loop.

---
 mysql-test/r/having.result | 20 ++++++++++++++++++++
 mysql-test/t/having.test   | 26 ++++++++++++++++++++++++++
 sql/item_cmpfunc.h         | 18 +++++++++++++++---
 sql/sql_select.cc          |  8 +++++---
 4 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/mysql-test/r/having.result b/mysql-test/r/having.result
index 9c3cc8fc89e..68ba34e353c 100644
--- a/mysql-test/r/having.result
+++ b/mysql-test/r/having.result
@@ -430,4 +430,24 @@ SELECT b, COUNT(DISTINCT a) FROM t1 GROUP BY b HAVING b is NULL;
 b	COUNT(DISTINCT a)
 NULL	1
 DROP TABLE t1;
+#
+# Bug#50995 Having clause on subquery result produces incorrect results.
+#
+CREATE TABLE t1
+(
+id1 INT,
+id2 INT NOT NULL,
+INDEX id1(id2)
+);
+INSERT INTO t1 SET id1=1, id2=1;
+INSERT INTO t1 SET id1=2, id2=1;
+INSERT INTO t1 SET id1=3, id2=1;
+SELECT t1.id1,
+(SELECT 0 FROM DUAL
+WHERE t1.id1=t1.id1) AS amount FROM t1
+WHERE t1.id2 = 1
+HAVING amount > 0
+ORDER BY t1.id1;
+id1	amount
+DROP TABLE t1;
 End of 5.0 tests
diff --git a/mysql-test/t/having.test b/mysql-test/t/having.test
index af9af4fe1fc..185ca4bdddb 100644
--- a/mysql-test/t/having.test
+++ b/mysql-test/t/having.test
@@ -442,4 +442,30 @@ INSERT INTO t1 VALUES (1, 1), (2,2), (3, NULL);
 SELECT b, COUNT(DISTINCT a) FROM t1 GROUP BY b HAVING b is NULL;
 DROP TABLE t1;
 
+
+--echo #
+--echo # Bug#50995 Having clause on subquery result produces incorrect results.
+--echo #
+
+CREATE TABLE t1
+(
+ id1 INT,
+ id2 INT NOT NULL,
+ INDEX id1(id2)
+);
+
+INSERT INTO t1 SET id1=1, id2=1;
+INSERT INTO t1 SET id1=2, id2=1;
+INSERT INTO t1 SET id1=3, id2=1;
+
+SELECT t1.id1,
+(SELECT 0 FROM DUAL
+ WHERE t1.id1=t1.id1) AS amount FROM t1
+WHERE t1.id2 = 1
+HAVING amount > 0
+ORDER BY t1.id1;
+
+DROP TABLE t1;
+
+
 --echo End of 5.0 tests
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h
index 38025ff0af5..425f54fb079 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -1474,9 +1474,21 @@ public:
   Item_cond(THD *thd, Item_cond *item);
   Item_cond(List<Item> &nlist)
     :Item_bool_func(), list(nlist), abort_on_null(0) {}
-  bool add(Item *item) { return list.push_back(item); }
-  bool add_at_head(Item *item) { return list.push_front(item); }
-  void add_at_head(List<Item> *nlist) { list.prepand(nlist); }
+  bool add(Item *item)
+  {
+    DBUG_ASSERT(item);
+    return list.push_back(item);
+  }
+  bool add_at_head(Item *item)
+  {
+    DBUG_ASSERT(item);
+    return list.push_front(item);
+  }
+  void add_at_head(List<Item> *nlist)
+  {
+    DBUG_ASSERT(nlist->elements);
+    list.prepand(nlist);
+  }
   bool fix_fields(THD *, Item **ref);
 
   enum Type type() const { return COND_ITEM; }
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index b9f59fac4d6..1d88343ad6d 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -8200,7 +8200,8 @@ static Item *eliminate_item_equal(COND *cond, COND_EQUAL *upper_levels,
   else
   {
     DBUG_ASSERT(cond->type() == Item::COND_ITEM);
-    ((Item_cond *) cond)->add_at_head(&eq_list);
+    if (eq_list.elements)
+      ((Item_cond *) cond)->add_at_head(&eq_list);
   }
 
   cond->quick_fix_field();
@@ -15657,7 +15658,7 @@ static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab)
 
   Item_cond_and *cond=new Item_cond_and();
   TABLE *table=join_tab->table;
-  int error;
+  int error= 0;
   if (!cond)
     DBUG_RETURN(TRUE);
 
@@ -15675,7 +15676,8 @@ static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab)
     cond->fix_fields(thd, (Item**)&cond);
   if (join_tab->select)
   {
-    error=(int) cond->add(join_tab->select->cond);
+    if (join_tab->select->cond)
+      error=(int) cond->add(join_tab->select->cond);
     join_tab->select_cond=join_tab->select->cond=cond;
   }
   else if ((join_tab->select= make_select(join_tab->table, 0, 0, cond, 0,