DROP TABLE IF EXISTS t1;

CREATE TABLE t1 (a INT);

INSERT INTO t1 VALUES (1),(2);

EXPLAIN EXTENDED SELECT * FROM t1 WHERE a=1 AND 1 IN (1,a,'3');

SHOW WARNINGS;

+-------+------+----------------------------------------------------------------------------+

| Level | Code | Message                                                                    |

+-------+------+----------------------------------------------------------------------------+

| Note  | 1003 | select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` = 1) |

+-------+------+----------------------------------------------------------------------------+

+-------+------+-----------------------------------------------------------------------------------------------------------------+

| Level | Code | Message                                                                                                         |

+-------+------+-----------------------------------------------------------------------------------------------------------------+

| Note  | 1003 | select `test`.`t1`.`a` AS `a` from `test`.`t1` where ((`test`.`t1`.`a` = 1) and (1 in (1,`test`.`t1`.`a`,'3'))) |

+-------+------+-----------------------------------------------------------------------------------------------------------------+