I was trying this: IF (OLD.value != NEW.value) THEN -- END IF; and couldn't get the condition to evaluate to true at all if OLD.value was NULL. I also tried: IF (OLD.value NOT LIKE NEW.value) THEN -- END IF; with the same result. But this works: IF ((OLD.value is NULL and NEW.value is NOT NULL) or (OLD.value != NEW.value)) THEN -- END IF; So, does NULL != 'abc' always evaluate to false? The manual (http://www.postgresql.org/docs/8.0/interactive/functions-comparison.html) states don't compare NULL values using =, but nothing about using != CSN __________________________________ Yahoo! Music Unlimited Access over 1 million songs. Try it free. http://music.yahoo.com/unlimited/ ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
