From: Tom Lane <tgl@sss.pgh.pa.us>
To: Ragnar Hafstað <gnari@simnet.is>
Cc: Joel Fradkin <jfradkin@wazagua.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: getting count for a specific querry
Date: Fri, 08 Apr 2005 12:32:03 -0400
Message-ID: <15084.1112977923@sss.pgh.pa.us> (raw)
In-Reply-To: <1112977546.7447.39.camel@localhost.localdomain>
References: <000001c53c3e$f4f5b730$797ba8c0@jfradkin>
<1112977546.7447.39.camel@localhost.localdomain>
Ragnar =?ISO-8859-1?Q?Hafsta=F0?= <gnari@simnet.is> writes:
> you might reduce the performance loss if your dataset is ordered by
> a UNIQUE index.
> select * from mytable where somecondition
> ORDER by uniquecol limit 50;
> and next:
> select * from mytable where somecondition AND uniquecol>?
> ORDER by uniquecol limit 50 OFFSET 50;
> where the ? is placeholder for last value returned by last query.
Uh, you don't want the OFFSET there do you? But otherwise, yeah,
this is a popular solution for paging through some rows. Doesn't really
help with the problem of counting the total dataset though ...
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, gnari@simnet.is, jfradkin@wazagua.com
Subject: Re: getting count for a specific querry
In-Reply-To: <15084.1112977923@sss.pgh.pa.us>
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