2009/8/24 Tom Lane <t...@sss.pgh.pa.us>: > Alvaro Herrera <alvhe...@commandprompt.com> writes: >> Bruce Momjian wrote: >>> So the problem is that our DELETE ... USING does not allow ANSI join >>> syntax? Can that be added? > >> Not sure about that. USING is already an extension to the standard, so >> if we extend it a bit more, it can't be a problem, can it? > > I don't see any very good way to extend the USING syntax to allow the > target table to be outer-joined to something else. Some other systems > allow it by letting you re-specify the target in the other clause, > equivalently to > > DELETE FROM target t USING t LEFT JOIN other_table ot ON ... > > but we have always considered that the target is *not* to be identified > with any member of the FROM/USING clause, so it would be a serious > compatibility break to change that now.
I'm all in favor of compatibility, but if there is any way to make this work without massive collateral damage, I am also all in favor of that. I am forever writing queries that contain a needless self-join to work around the impossibility of directly outer-joining against the target. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
