I was once told by an Oracle contractor that Oracle does not optimize NOT IN queries
well, and that the most efficient way of doing this is to use the NOT EXISTS form that
I suggested. This advice was for Oracle 7, I admit.
I have used it and it does make a VERY noticable difference.
>Actually, I'm not sure how Oracle or PG would handle this, but in
>DB2, the nested loop join you warn against would depend on
>how the optimizer is set up. It should set up temp tables and
>do a hash join, which would be a lot quicker.
------------------------------------------------------------
--== Sent via Deja.com ==--
http://www.deja.com/
