| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | jim(at)nasby(dot)net |
| Cc: | Josh Berkus <josh(at)agliodbs(dot)com>, pgsql-performance <pgsql-performance(at)postgresql(dot)org>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [PERFORM] Hypothetical suggestions for planner, indexing improvement |
| Date: | 2003-05-06 13:45:07 |
| Message-ID: | 24779.1052228707@sss.pgh.pa.us |
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| Lists: | pgsql-hackers pgsql-performance |
"Jim C. Nasby" <jim(at)nasby(dot)net> writes:
> It would be nice to add support for multi-column IN..
> WHERE (a, b, c) IN (SELECT a, b, c ...)
RTFM...
> BTW, does postgresql handle IN and EXISTS differently?
Yes.
> Theoretically if the optimizer was good enough you could transform one
> to the other and not worry about it.
No. They have different responses to NULLs in the subselect result.
regards, tom lane
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