RE: Large OR query - Mailing list pgsql-general

From Tamsin
Subject RE: Large OR query
Date
Msg-id NEBBKHBOBMJCHDMGKCNJGEEMCPAA.tg_mail@bryncadfan.co.uk
Whole thread Raw
In response to Re: Large OR query  ("Mitch Vincent" <mvincent@cablespeed.com>)
List pgsql-general
isn't that sort of IN statement not very efficient in postgresql?
normally instead of that sort of IN statement i do:

SELECT * FROM maintable WHERE exists (SELECT id FROM temptable WHERE
temptable.id = maintable.id);

but anyway, its not actually needed is it? can't you just do:

SELECT maintable.* FROM maintable, temptable WHERE maintable.id =
temptable.id;

tamsin

> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Mitch Vincent
> Sent: 12 June 2001 15:25
> To: Zak McGregor; pgsql-general@postgresql.org
> Subject: Re: [GENERAL] Large OR query
>
>
> Is populating another table with the 1000 values and doing a
> SELECT * FROM <whatever> WHERE <something> IN (SELECT <something> FROM
> <whatever>) ?
>
> I'm not entirely sure that it will yield a better result but it's worth a
> try.
>
> -Mitch
>
> ----- Original Message -----
> From: "Zak McGregor" <zak@mighty.co.za>
> To: <pgsql-general@postgresql.org>
> Sent: Tuesday, June 12, 2001 8:42 AM
> Subject: [GENERAL] Large OR query
>
>
> > Hi all
> >
> > If I have say 1000 values for an ID field, what is the best way to
> > select from a table all the corresponding records?
> > I have tried
> > select * from blah where id in (id1,id2,id3...id1000)
> > and
> > select * from blah where id=id1 or id=id2 ... or id=id1000
> >
> > and both are pretty slow.
> > Is there a better way to do this please?
> >
> > Thanks
> >
> > Ciao
> > --
> > Zak McGregor    http://www.carfolio.com - Over 7000 car specs online
> > Web mercenary - currently for hire. Perl/html/.js/sql/cgi/GNUlinux/php +
> > ---------------------------------------------------------------------
> > "Trying to make bits uncopyable is like trying to make water not wet.
> > The sooner people accept this, and build business models that take
> > this into account, the sooner people will start making money again."
> >     -- Bruce Schneier
> >
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