IS_NULL
Checks whether a value is NULL.
Syntax
IS_NULL( <expr> )
Arguments
| Arguments | Description |
|---|---|
<expr> | Any general expression which will be evaluated as the value. |
Return Type
If x is NULL, IS_NULL() returns 1, otherwise it returns 0.
Examples
CREATE TABLE nullable_test (a INT NULL, b INT UNSIGNED NULL);
INSERT INTO nullable_test VALUES(1, NULL), (NULL, 2), (3, 3);
SELECT a FROM nullable_test WHERE is_null(b);
+------+
| a |
+------+
| 1 |
+------+