Wrong result with outer join + subquery in ON clause in maria-5.3
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
MariaDB |
Fix Released
|
High
|
Igor Babaev |
Bug Description
Not repeatable with maria-5.3, mysql 5.1 . Not influenced by optimizer switches. The following query:
SELECT t3.b FROM t2 LEFT JOIN t3 ON ( 6 ) IN ( SELECT a FROM t1 );
returns t3.b = 0 even though the ON clause is FALSE and therefore there are no records to be joined between the two tables.
explain:
| 1 | PRIMARY | t2 | system | NULL | NULL | NULL | NULL | 1 | |
| 1 | PRIMARY | t3 | system | NULL | NULL | NULL | NULL | 1 | |
| 2 | DEPENDENT SUBQUERY | t1 | ALL | NULL | NULL | NULL | NULL | 2 | Using where |
actual result:
mysql> SELECT t3.b FROM t2 LEFT JOIN t3 ON ( 6 ) IN ( SELECT a FROM t1 );
+------+
| b |
+------+
| 0 |
+------+
expected result:
SELECT t3.b FROM t2 LEFT JOIN t3 ON ( 6 ) IN ( SELECT a FROM t1 );
+------+
| b |
+------+
| NULL |
+------+
test case:
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 ( a int);
INSERT INTO t1 VALUES (0),(0);
DROP TABLE IF EXISTS t2;
CREATE TABLE t2 (b int);
INSERT INTO t2 VALUES (0);
DROP TABLE IF EXISTS t3;
CREATE TABLE t3 (b int);
INSERT INTO t3 VALUES (0);
SELECT t3.b FROM t2 LEFT JOIN t3 ON ( 6 ) IN ( SELECT a FROM t1 );
bzr version-info
revision-id: <email address hidden>
date: 2011-07-20 11:56:28 +0400
build-date: 2011-07-20 14:25:55 +0300
revno: 3123
branch-nick: maria-5.3
optimizer switch in effect:
index_merge=
Changed in maria: | |
milestone: | none → 5.3 |
assignee: | nobody → Timour Katchaounov (timour) |
Changed in maria: | |
assignee: | Timour Katchaounov (timour) → Igor Babaev (igorb-seattle) |
status: | Confirmed → In Progress |
Changed in maria: | |
status: | In Progress → Fix Committed |
Changed in maria: | |
status: | Fix Committed → Fix Released |
Not repeatable with maria-5.2, mysql.