Boolean values are typically the TRUE and FALSE constants.
TRUE is evaluated to 1 and FALSE is evaluated to 0. The constant names are case-insensitive.
obclient> SELECT TRUE, true, FALSE, false;
+------+------+-------+-------+
| TRUE | true | FALSE | false |
+------+------+-------+-------+
| 1 | 1 | 0 | 0 |
+------+------+-------+-------+
1 row in set