MySQL | ISNULL( ) Function

The MySQL ISNULL() function is used for checking whether an expression is NULL or not. This function returns 1 if the expression passed is NULL, else it returns 0.

The ISNULL() function accepts the expression as a parameter and returns an integer a value 0 or 1 depending on the parameter passed.

Syntax:

ISNULL(expression)

Parameters Used:

expression – It is used to specify the expression.

Return Value:
The MySQL ISNULL() function returns 1 if the expression passed is a NULL expression, else it returns 0.

Supported Versions of MySQL:

• MySQL 5.7
• MySQL 5.6
• MySQL 5.5
• MySQL 5.1
• MySQL 5.0
• MySQL 4.1
• MySQL 4.0
• MySQL 3.23

Example-1: Implementing ISNULL() function.

SELECT ISNULL(NULL); 

Output:

1 

Example-2: Implementing ISNULL() function on a string.

SELECT ISNULL("gfg"); 

Output:

0 

Example-3: Implementing ISNULL() function on an integer value.

SELECT ISNULL(123); 

Output:

0