"Decibel!" <[EMAIL PROTECTED]> writes: > On Aug 8, 2008, at 3:23 PM, Tom Lane wrote: >> * has no set operations (UNION etc), grouping, set-returning functions >> in the SELECT list, LIMIT, or a few other funny cases > > > Couldn't union/union all be treated as > > EXISTS(a) > OR EXISTS(b)
Kind of confused by what you mean here. Can you give an example? The usual transformation to consider with UNION is to transform SELECT ... WHERE x OR y into SELECT ... WHERE x UNION ALL SELECT ... WHERE y AND NOT x (modulo handling NULLs properly) -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's RemoteDBA services! -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
