Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc)
От | Bruno Wolff III |
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Тема | Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc) |
Дата | |
Msg-id | 20020825150739.GA28640@wolff.to обсуждение исходный текст |
Ответ на | Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc) (Martijn van Oosterhout <kleptog@svana.org>) |
Ответы |
Re: CREATE INDEX .. ON table1 (field1 asc, field2 desc)
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Список | 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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