IS NOT
Description
The IS NOT
tests a value against a boolean value, where boolean_value can be TRUE, FALSE, or UNKNOWN.
Syntax
> IS NOT boolean_value
Examples
mysql> SELECT 1 IS NOT TRUE, 0 IS NOT FALSE, NULL IS NOT UNKNOWN;
+-----------+------------+----------+
| 1 != true | 0 != false | null != |
+-----------+------------+----------+
| false | false | NULL |
+-----------+------------+----------+
1 row in set (0.01 sec)