IS NULL Operator

The IS NULL operator is a unary operator. A unary operation is an operation that includes only one operand. If you use the IS NULL operator, and if the operand for this operator evaluates to:

• TRUE. IS NULL evaluates to NULL.

• FALSE. IS NULL evaluates to not NULL.

You cannot use the = (equal) operator to determine if a value is NULL because a NULL operand does not contain a value.