Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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None
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None
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None
Description
The following sequence of commands gives us a wrong result set in mariadb-5.2:
CREATE TABLE t1(a INT);
INSERT INTO t1 VALUES(9);
CREATE TABLE t2(b INT);
INSERT INTO t2 VALUES(8);
CREATE TABLE t3(c INT);
INSERT INTO t3 VALUES(3);
SELECT * FROM t2 RIGHT JOIN t3 ON(c = b) WHERE b < ALL(SELECT a FROM t1 WHERE a <= 7);
MariaDB [test]> SELECT * FROM t2 RIGHT JOIN t3 ON(c = b) WHERE b < ALL(SELECT a FROM t1 WHERE a <= 7);
Empty set (0.00 sec)
MariaDB [test]> EXPLAIN EXTENDED SELECT * FROM t2 RIGHT JOIN t3 ON(c = b) WHERE b < ALL(SELECT a FROM t1 WHERE a <= 7);
-------------------------------------------------------------------------------------------------------------------
| 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 | SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE noticed after reading const tables |
-------------------------------------------------------------------------------------------------------------------
2 rows in set, 1 warning (0.00 sec)
MariaDB [test]> show warnings;
---------------------------------------------------------------------------------
| Level | Code | Message |
---------------------------------------------------------------------------------
| Note | 1003 | select '8' AS `b`,'3' AS `c` from `test`.`t3` join `test`.`t2` where 0 |
---------------------------------------------------------------------------------
The bug is not reproducible in mariadb-5.3:
MariaDB [test]> select version();
---------------------
| version() |
---------------------
| 5.3.6-MariaDB-debug |
---------------------
MariaDB [test]> SELECT * FROM t2 RIGHT JOIN t3 ON(c = b) WHERE b < ALL(SELECT a FROM t1 WHERE a <= 7);
----------+
| b | c |
----------+
| NULL | 3 |
----------+
MariaDB [test]> EXPLAIN EXTENDED SELECT * FROM t2 RIGHT JOIN t3 ON(c = b) WHERE b < ALL(SELECT a FROM t1 WHERE a <= 7);
---------------------------------------------------------------------------------------------------------------------
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
---------------------------------------------------------------------------------------------------------------------
| 1 | PRIMARY | t3 | system | NULL | NULL | NULL | NULL | 1 | 100.00 | |
| 1 | PRIMARY | t2 | system | NULL | NULL | NULL | NULL | 1 | 100.00 | |
| 2 | SUBQUERY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE noticed after reading const tables |
---------------------------------------------------------------------------------------------------------------------
MariaDB [test]> show warnings;
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| Level | Code | Message |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| Note | 1003 | select NULL AS `b`,3 AS `c` from `test`.`t3` left join `test`.`t2` on(0) where <not>(<in_optimizer>(NULL,(<min>(select 9 from `test`.`t1` where (9 <= 7)) <= <cache>(NULL)))) |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(See also bug #13735712 for mysql code line)