From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | Bruno Wolff III <bruno(at)wolff(dot)to> |
Cc: | Timur <itvthor(at)sdf(dot)lonestar(dot)org>, pgsql-general(at)postgresql(dot)org |
Subject: | Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc) |
Date: | 2002-09-02 02:50:30 |
Message-ID: | 200209020250.g822oU121626@candle.pha.pa.us |
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Thread: | |
Lists: | pgsql-general |
Is this a TODO item?
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Bruno Wolff III wrote:
> On Sun, Aug 25, 2002 at 10:00:56 +1000,
> Martijn van Oosterhout <kleptog(at)svana(dot)org> wrote:
> > On Sat, Aug 24, 2002 at 08:18:25PM +0500, Timur wrote:
> > > Hello!
> > >
> > > I am new to PostgreSQL and databases in general, and I have this
> > > question: why it is not possible to specify ordering when creating an
> > > index?
> > >
> > > Let's say I have a query which looks like this:
> > > SELECT * FROM table1
> > > ORDER BY field1, field2 DESC
> > > LIMIT 100;
> > >
> > > Apparently, system won't use index ON (field1, field2) ..
> >
> > It will if you do:
> > SELECT * FROM table1
> > ORDER BY field1 DESC, field2 DESC
> > LIMIT 100;
> >
> > Time to go read that SQL book again?
>
> That may or may not be his problem. If the order he wants is
> order by field1 ASC, fiels2 DESC there isn't a simple way to create
> a matching index.
>
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