Andrew Gierth wrote: > >>>>> "Guillaume" == Guillaume Smet <guillaume.s...@gmail.com> writes: > > Guillaume> - "While semi-joins merely replace existing IN joins, > Guillaume> anti-joins are a new capability for NOT IN and NOT EXIST > Guillaume> clauses (Tom) This improves optimization possibilities." > Guillaume> -> remove the "(Tom)", s/EXIST/EXISTS/ > > Also s/NOT IN and // (anti-joins are not used for NOT IN due to the > awkward semantics of nulls). Should possibly also mention the fact that > some outer joins can be planned as anti-joins too.
Thanks, text updated: While semi-joins merely replace existing IN joins, anti-joins are a new capability for NOT EXISTS clauses (Tom) This improves optimization possibilities. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers