On Wed, 19 Oct 2005, [iso-8859-2] Havasv?lgyi Ott? wrote: > Hi, > > I have just run this command on 8.0.4 : > > SELECT 'foo' WHERE 0 NOT IN (NULL, 1); > > And it resulted is zero rows. > Without NULL it is OK. > Is this a bug, or the standard has such a rule?
This is standard behavior. Seeing if I can do this from memory... a NOT IN b is equivalent in the spec to NOT(a IN b). a IN b is equivalent to a =ANY b. a =ANY b returns true if a = x is true for any x in b. a =ANY b returns false if a = x is false for all x in b. Otherwise it returns unknown. 0 = NULL returns unknown 0 = 1 returns false So, 0 IN (NULL,1) returns unknown. NOT(unknown) is unknown. WHERE clauses only return rows for which the search condition is true, so a row is not returned. ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
