id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 5 NULL 21 Using where; Using index
1 SIMPLE t1 range a a 5 NULL 2 Using where; Using index
select * from t1 where not(not(a));
a
1
...
...
@@ -388,7 +388,7 @@ Table Op Msg_type Msg_text
test.t1 analyze status OK
explain extended select a, not(not(a)), not(a <= 2 and not(a)), not(a not like "1"), not (a not in (1,2)), not(a != 2) from t1 where not(not(a)) having not(not(a));
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 index NULL a 5 NULL 5 100.00 Using where; Using index
1 SIMPLE t1 index a a 5 NULL 5 40.00 Using where; Using index
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,(`test`.`t1`.`a` <> 0) AS `not(not(a))`,((`test`.`t1`.`a` > 2) or `test`.`t1`.`a`) AS `not(a <= 2 and not(a))`,(`test`.`t1`.`a` like '1') AS `not(a not like "1")`,(`test`.`t1`.`a` in (1,2)) AS `not (a not in (1,2))`,(`test`.`t1`.`a` = 2) AS `not(a != 2)` from `test`.`t1` where `test`.`t1`.`a` having `test`.`t1`.`a`
Note 1003 select `test`.`t1`.`a` AS `a`,(`test`.`t1`.`a` <> 0) AS `not(not(a))`,((`test`.`t1`.`a` > 2) or `test`.`t1`.`a`) AS `not(a <= 2 and not(a))`,(`test`.`t1`.`a` like '1') AS `not(a not like "1")`,(`test`.`t1`.`a` in (1,2)) AS `not (a not in (1,2))`,(`test`.`t1`.`a` = 2) AS `not(a != 2)` from `test`.`t1` where (`test`.`t1`.`a` <> 0) having (`test`.`t1`.`a` <> 0)