On Thu, Dec 15, 2005 at 09:25:42AM -0500, Tom Lane wrote:
> Greg Stark <gsstark@mit.edu> writes:
> > Tom Lane <tgl@sss.pgh.pa.us> writes:
> >> There is some stuff in the literature about how to make transformations
> >> of the last kind, but it requires additional executor smarts to do strange
> >> sorts of "generalized outer join" operations.
>
> > Would these "generalized outer join" operations be general enough to handle IN
> > semantics? Or other subqueries?
>
> No, AFAICT it's just a weird way of defining a join operation.
>
> I did find some papers that talked about ways to push joins up and down
> past aggregations and GROUP BY, but that's a problem for another day.
Might be worth adding a TODO for that and including links to the papers.
There's enough people that seem to drop in with PhD thesis and what-not
pulled from the TODO that someone could end up doing this work for us.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461