INSERT INTO t2 VALUES (3), (1),(2), (5), (4), (7), (6);
EXPLAIN EXTENDED
SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1));
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
1 PRIMARY t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 Using index
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 3 Using where
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
1 PRIMARY t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 100.00 Using index
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t1`.`a`) and (not(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 AS `Not_used` from `test`.`t1` where ((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`)) having <is_not_null_test>(`test`.`t1`.`a`))))))
SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1));
