MySQL ISNULL() Function

Test whether an expression is NULL:

SELECT ISNULL(NULL);

Definition and Usage

The ISNULL() function returns 1 or 0 depending on whether an expression is NULL.

If expression is NULL, this function returns 1. Otherwise, it returns 0.

ISNULL(expression)

Parameter	Description
expression	Required. The value to test

Works in:	From MySQL 4.0

Test whether an expression is NULL:

SELECT ISNULL("");

Test whether an expression is NULL:

SELECT ISNULL(350);

Test whether an expression is NULL:

SELECT ISNULL("Hello world!");