NULL

The special NULL value represents that a variable has no value. NULL is the only possible value of type NULL.

????: The null type was introduced in PHP 4.

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 keyword NULL.

$var = NULL; ?>

See also is_null() and unset().