| From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
|---|---|
| To: | Michael Meskes <meskes(at)postgresql(dot)org> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Re: Does PostgreSQL support EXISTS? |
| Date: | 2001-06-13 14:03:24 |
| Message-ID: | 200106131403.f5DE3Pr03671@candle.pha.pa.us |
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| Lists: | pgsql-general |
> On Wed, Jun 13, 2001 at 12:23:15PM +1000, Martijn van Oosterhout wrote:
> > select x from a where v in (select v from b)
> > select x from a where exists (select 1 from b where a.v = b.v)
>
> The latter should be faster than the former on every relational database
> system.
That surprises me because the subquery is a correlated subquery which
are usually slower on other databases that normal subqueries.
--
Bruce Momjian | http://candle.pha.pa.us
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