| From: | Thomas Lockhart <lockhart(at)alumni(dot)caltech(dot)edu> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | pgsql-hackers(at)postgreSQL(dot)org |
| Subject: | Re: A fine point about OUTER JOIN semantics |
| Date: | 2000-09-05 14:29:22 |
| Message-ID: | 39B50342.69108852@alumni.caltech.edu |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
> Well, I guess so, but I can't get excited about adding machinery to
> detect cases like this ... are there any less-silly examples that make
> a more compelling case for expending planner cycles to see if an outer
> join can be reduced to an inner join?
Well, in all cases the outer join reduces to an inner join if there is a
qualification which would eliminate nulls from any intermediate result.
It would be neat to see this happen automagically, but perhaps that
would be a gratuitously studly feature ;)
- Thomas
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