OTSyntax
------

IS NOT boolean_value

Description
-----------

Tests a value against a boolean value, where boolean_value can be TRUE, FALSE,
or UNKNOWN.

Examples
--------

SELECT 1 IS NOT UNKNOWN, 0 IS NOT UNKNOWN, NULL IS NOT UNKNOWN;
+------------------+------------------+---------------------+
| 1 IS NOT UNKNOWN | 0 IS NOT UNKNOWN | NULL IS NOT UNKNOWN |
+------------------+------------------+---------------------+
|                1 |                1 |                   0 |
+------------------+------------------+---------------------+

SELECT NULL IS NOT TRUE, NULL IS NOT FALSE;
+------------------+-------------------+
| NULL IS NOT TRUE | NULL IS NOT FALSE |
+------------------+-------------------+
|                1 |                 1 |
+------------------+-------------------+

URL: https://mariadb.com/kb/en/is-not/https://mariadb.com/kb/en/is-not/