Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc) - Mailing list pgsql-general

From Bruno Wolff III
Subject Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc)
Date
Msg-id 20020825150739.GA28640@wolff.to
Whole thread Raw
In response to Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc)  (Martijn van Oosterhout <kleptog@svana.org>)
Responses Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc)  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-general
On Sun, Aug 25, 2002 at 10:00:56 +1000,
  Martijn van Oosterhout <kleptog@svana.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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