From: | "Steinar H(dot) Gunderson" <sgunderson(at)bigfoot(dot)com> |
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To: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: [GENERAL] Query is not using index when it should |
Date: | 2004-12-11 14:32:13 |
Message-ID: | 20041211143213.GA2659@uio.no |
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Lists: | pgsql-general pgsql-performance pgsql-sql |
On Sat, Dec 11, 2004 at 03:17:13PM +0100, Tomas Skäre wrote:
> select c.* from cjm_object c
> inner join
> (select max(timestamp) as timestamp,objectid,field from cjm_object
> group by objectid,field) t
> using(timestamp,objectid,field)
> where 1=1 and data is not null
> order by objectid,field;
Usually, SELECT max(field) FROM table is better written in PostgreSQL as
SELECT field FROM table ORDER field DESC LIMIT 1.
I don't see the point of "where 1=1", though...
/* Steinar */
--
Homepage: http://www.sesse.net/
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