"Josh Berkus" <[EMAIL PROTECTED]> writes: > Er... what were you expecting, exactly? AFAICT, the quoted behavior is correct per the defined behavior of nullif(), cf http://www.ca.postgresql.org/users-lounge/docs/7.1/postgres/functions-conditional.html NULLIF(value1, value2) The NULLIF function returns NULL if and only if value1 and value2 are equal. Otherwise it returns value1. > Except for IS NULL (and COALESCE, which uses IS NULL) any operation > involving a NULL is also NULL. Well, that's not quite the correct reasoning. NULLIF and COALESCE are both shorthands for CASE expressions, and hence are capable of returning non-NULL for a NULL input. It all depends on how the CASE tests are phrased. NULLIF is essentially CASE WHEN value1 = value2 THEN NULL ELSE value1 END In the quoted example, "NULL = 5" will yield NULL, which is interpreted as a FALSE case test, so you get the ELSE case, ie value1, ie NULL. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
