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!");