"Joshua D. Drake" <jd@xxxxxxxxxxxxxxxxx> writes: > This looks like a NULL vs '' issue. Am I wrong? No, it's a NULL vs NOT IN issue. Specifically, if the subquery yields any NULLs and the comparison operator is strict (which nearly all are) then it's impossible to get a TRUE result from the NOT IN --- the only possibilities are FALSE (if a match is found among the non-nulls) or NULL (if not). Standard gotcha for newbie SQL coders. My recommendation is to use NOT EXISTS instead; it's got less surprising semantics (and, as of 8.4, it'll get optimized significantly better than NOT IN). regards, tom lane -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
