In response to Bruce Momjian <bruce@momjian.us>:
> Alvaro Herrera wrote:
> > Bruce Momjian wrote:
> >
> > > > Ultimately, why not allow:
> > > >
> > > > DELETE h, tn
> > > > FROM history AS h
> > > > INNER JOIN term_node AS tn ON (h.nid = tn.nid)
> > > > INNER JOIN term_data AS td ON (td.tid = tn.tid)
> > > > WHERE h.uid = 2067 AND td.vid = 2
> > > >
> > > > IMHO this would improve compliance towards other database systems. To me
> > > > this seems to be in the reasonable scope of compatibility.
> > >
> > > Which "other database systems"? Only MySQL? If it is MySQL-only, we
> > > are unlikely to add it.
> >
> > The SQL standard does not support this syntax. They would have you put
> > the joins in a subselect (which is often not enough because then you
> > can't use outer joins).
>
> So the problem is that our DELETE ... USING does not allow ANSI join
> syntax? Can that be added?
I suspect that the reason MySQL has this syntax is because for a long time
they didn't have proper foreign keys and referential integrity.
With proper foreign keys and ON DELETE CASCADE, why would supporting
such syntax even be necessary?
--
Bill Moran
http://www.potentialtech.com
http://people.collaborativefusion.com/~wmoran/