MySQL IFNULL() Function

The IFNULL() function in MySQL provides a way to handle potential NULL values in your data. It lets you specify a substitute value to use in place of NULL if a particular expression evaluates to NULL.

IFNULL(): Definition and Usage

NULL values can sometimes cause problems in queries or applications. IFNULL() allows you to replace NULL values with a value of your choosing, making your data more consistent and easier to work with. If the expression is not NULL, the function simply returns the expression's value.

Syntax


IFNULL(expression, alt_value)

Parameter Values

Parameter	Description
`expression`	The value or expression you want to check for `NULL`. This is required.
`alt_value`	The value to return if the `expression` is `NULL`. This is required.

Examples

Handling a NULL Value

This example replaces a NULL value with "W3Schools.com".

Syntax


SELECT IFNULL(NULL, "W3Schools.com");

Output


W3Schools.com

Handling a Non-NULL Value

If the expression is not NULL, the expression's value is returned.

Syntax


SELECT IFNULL("Hello", "W3Schools.com");

Output


Hello

Replacing NULL with a Number

Replacing a NULL with a numeric value.

Syntax


SELECT IFNULL(NULL, 500);