NULL

The special null value represents a variable with no value. null is the only possible value of type null.

A variable is considered to be null if:

  • it has been assigned the constant null.

  • it has not been set to any value yet.

  • it has been unset().

Syntax

There is only one value of type null, and that is the case-insensitive constant null.

<?php
$var = NULL;       
?>

See also the functions is_null() and unset().

Casting to null

Warning

This feature has been DEPRECATED as of PHP 7.2.0, and REMOVED as of PHP 8.0.0. Relying on this feature is highly discouraged.

Casting a variable to null using (unset) $var will not remove the variable or unset its value. It will only return a null value.