Function: Return a NULL value for a sub-expression if it has a specific value otherwise return the value of the sub-expression Author: Arno Brinkman Format: ::= NULLIF Syntax Rules: 1) NULLIF (V1, V2) is equivalent to the following : CASE WHEN V1 = V2 THEN NULL ELSE V1 END Examples: A) UPDATE PRODUCTS SET STOCK = NULLIF(STOCK,0)