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)

Return the specified value IF the expression is NULL, otherwise return the expression:

SELECT IFNULL(NULL, "Iampsp.com");

The IFNULL() function returns a specified value if the expression is NULL.

If the expression is NOT NULL, this function returns the expression.

IFNULL(expression, alt_value)