From: Steinar H. Gunderson <sgunderson@bigfoot.com>
To: pgsql-performance@postgresql.org
Subject: Re: [GENERAL] Query is not using index when it should
Date: Sat, 11 Dec 2004 15:32:13 +0100
Message-ID: <20041211143213.GA2659@uio.no> (raw)
In-Reply-To: <80d5xgudg6.fsf@junk.nocrew.org>
References: <80oeh2tm7x.fsf@junk.nocrew.org>
<20041210182453.G92467@megazone.bigpanda.com>
<80d5xgudg6.fsf@junk.nocrew.org>
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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To: pgsql-sql@postgresql.org
Cc: sgunderson@bigfoot.com, pgsql-performance@postgresql.org
Subject: Re: [GENERAL] Query is not using index when it should
In-Reply-To: <20041211143213.GA2659@uio.no>
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