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Date: Mon, 9 Sep 2002 08:57:31 -0500
From: Bruno Wolff III <bruno@wolff.to>
To: Colin Fox <cfox@cfconsulting.ca>
Cc: pgsql-sql@postgresql.org
Subject: Re: Efficiency Question
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On Mon, Sep 09, 2002 at 00:13:04 +0000,
  Colin Fox <cfox@cfconsulting.ca> wrote:
> 
> select
>    *
> from
>    motm
> order by
>    creation_date desc
> limit 1;
> 
> So in the first case I select the record that has the largest date. In the
> second case, I order all the records, and then return only one.

If you have an index on creation_date an index scan can be used which
will make the second form run a lot faster if there are lots of records.