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Bug #21302: Result not properly sorted when using an ORDER BY on a second

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table in a join
 The optimizer removes redundant columns in ORDER BY. It is considering 
redundant every reference to const table column, e.g b in :
create table t1 (a int, b int, primary key(a)); 
select 1 from t1 order by b where a = 1

But it must not remove references to const table columns if the 
const table is an outer table because there still can be 2 values :
the const value and NULL. e.g.:
create table t1 (a int, b int, primary key(a));
select t2.b c from t1 left join t1 t2 on (t1.a = t2.a and t2.a = 5) 
  order by c;


mysql-test/r/join_outer.result:
  Bug #21302: Result not properly sorted when using an ORDER BY on a second 
              table in a join
   - don't remove columns of const tables in ORDER BY if the const table 
     is an outer table.
mysql-test/r/order_by.result:
  Bug #21302: Result not properly sorted when using an ORDER BY on a second 
              table in a join
   - test case
mysql-test/t/order_by.test:
  Bug #21302: Result not properly sorted when using an ORDER BY on a second 
              table in a join
   - test case
sql/sql_select.cc:
  Bug #21302: Result not properly sorted when using an ORDER BY on a second 
              table in a join
   - don't remove columns of const tables in ORDER BY if the const table 
     is an outer table.
This commit is contained in:
unknown
2006-08-14 15:45:48 +03:00
parent 1cf65f311d
commit 06a302eff2
4 changed files with 72 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
mysql-test/r/join_outer.result
View File

@ -735,7 +735,7 @@ explain select s.*, '*', m.*, (s.match_1_h - m.home) UUX from
(t2 s left join t1 m on m.match_id = 1)
order by m.match_id desc;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE s ALL NULL NULL NULL NULL 10
1 SIMPLE s ALL NULL NULL NULL NULL 10 Using temporary; Using filesort
1 SIMPLE m const match_id,match_id_2 match_id 1 const 1
explain select s.*, '*', m.*, (s.match_1_h - m.home) UUX from
(t2 s left join t1 m on m.match_id = 1)

37
mysql-test/r/order_by.result
View File

@ -852,3 +852,40 @@ b a
20 1
10 2
DROP TABLE t1;
CREATE TABLE t1 (a int, b int, PRIMARY KEY (a));
INSERT INTO t1 VALUES (1,1), (2,2), (3,3);
explain SELECT t1.b as a, t2.b as c FROM
t1 LEFT JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2)
ORDER BY c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using temporary; Using filesort
1 SIMPLE t2 const PRIMARY PRIMARY 4 const 1
SELECT t1.b as a, t2.b as c FROM
t1 LEFT JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2)
ORDER BY c;
a c
1 NULL
3 NULL
2 2
explain SELECT t1.b as a, t2.b as c FROM
t1 JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2)
ORDER BY c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1
1 SIMPLE t2 const PRIMARY PRIMARY 4 const 1
CREATE TABLE t2 LIKE t1;
INSERT INTO t2 SELECT * from t1;
CREATE TABLE t3 LIKE t1;
INSERT INTO t3 SELECT * from t1;
CREATE TABLE t4 LIKE t1;
INSERT INTO t4 SELECT * from t1;
INSERT INTO t1 values (0,0),(4,4);
SELECT t1.*,t2.* FROM t1 LEFT JOIN (t2, t3 LEFT JOIN t4 ON t3.a=t4.a)
ON (t1.a=t2.a AND t1.b=t3.b) order by t2.b;
a b a b
0 0 NULL NULL
4 4 NULL NULL
1 1 1 1
2 2 2 2
3 3 3 3
DROP TABLE t1,t2,t3,t4;

32
mysql-test/t/order_by.test
View File

@ -578,3 +578,35 @@ INSERT INTO t1 VALUES (1,30), (2,20), (1,10), (2,30), (1,20), (2,10);
DROP TABLE t1;
# End of 4.1 tests
#
# Bug#21302: Result not properly sorted when using an ORDER BY on a second
# table in a join
#
CREATE TABLE t1 (a int, b int, PRIMARY KEY (a));
INSERT INTO t1 VALUES (1,1), (2,2), (3,3);
explain SELECT t1.b as a, t2.b as c FROM
t1 LEFT JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2)
ORDER BY c;
SELECT t1.b as a, t2.b as c FROM
t1 LEFT JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2)
ORDER BY c;
# check that it still removes sort of const table
explain SELECT t1.b as a, t2.b as c FROM
t1 JOIN t1 t2 ON (t1.a = t2.a AND t2.a = 2)
ORDER BY c;
CREATE TABLE t2 LIKE t1;
INSERT INTO t2 SELECT * from t1;
CREATE TABLE t3 LIKE t1;
INSERT INTO t3 SELECT * from t1;
CREATE TABLE t4 LIKE t1;
INSERT INTO t4 SELECT * from t1;
INSERT INTO t1 values (0,0),(4,4);
SELECT t1.*,t2.* FROM t1 LEFT JOIN (t2, t3 LEFT JOIN t4 ON t3.a=t4.a)
ON (t1.a=t2.a AND t1.b=t3.b) order by t2.b;
DROP TABLE t1,t2,t3,t4;