While I agree that the commented out code is incorrectly written, I think it should be rewritten with a proper NULL test so that the logic actually does work. The implied logic is that if a particular non-null condition exists, use it. If a NULL condition does exist, preserve the NULL. If neither condition exists, then apply the alternative. The bottom line of what I read as the intent of the code is that if the null conditions exists, then DO NOT apply the alternative using ELSE.