database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2026-01-06 05:22:24 +03:00
Code Activity

Bug#51598 Inconsistent behaviour with a COALESCE statement inside an IN comparison

Browse Source 
Optimizer erroneously translated LEFT JOIN into INNER JOIN.
It leads to cutting rows with NULL right side. It happens
because Item_row uses not_null_tables() method form the
base(Item) class and does not calculate 'null tables'
properly. The fix is adding calculation of 'not null tables'
to Item_row.
This commit is contained in:
Sergey Glukhov
2010-03-19 10:21:37 +04:00
parent bed0948145
commit 879b705342
4 changed files with 44 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
mysql-test/r/join_outer.result
View File

@@ -1289,3 +1289,23 @@ a COUNT( t2.b ) SUM( t2.b ) MAX( t2.b )
1 3 6 3
NULL 3 6 3
DROP TABLE t1, t2;
#
# Bug#51598 Inconsistent behaviour with a COALESCE statement inside an IN comparison
#
CREATE TABLE t1(f1 INT, f2 INT, f3 INT);
INSERT INTO t1 VALUES (1, NULL, 3);
CREATE TABLE t2(f1 INT, f2 INT);
INSERT INTO t2 VALUES (2, 1);
EXPLAIN EXTENDED SELECT * FROM t1 LEFT JOIN t2 ON t1.f2 = t2.f2
WHERE (COALESCE(t1.f1, t2.f1), f3) IN ((1, 3), (2, 2));
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
1 SIMPLE t2 system NULL NULL NULL NULL 1 100.00
Warnings:
Note 1003 select '1' AS `f1`,NULL AS `f2`,'3' AS `f3`,NULL AS `f1`,NULL AS `f2` from `test`.`t1` left join `test`.`t2` on(multiple equal(NULL)) where ((coalesce('1',NULL),'3') in ((1,3),(2,2)))
SELECT * FROM t1 LEFT JOIN t2 ON t1.f2 = t2.f2
WHERE (COALESCE(t1.f1, t2.f1), f3) IN ((1, 3), (2, 2));
f1 f2 f3 f1 f2
1 NULL 3 NULL NULL
DROP TABLE t1, t2;
End of 5.1 tests