From: Tom Lane <tgl@sss.pgh.pa.us>
To: Steve Midgley <public@misuse.org>
Cc: pgsql-sql@postgresql.org
Subject: Re: (repost) Help understanding expressions in order by clause
Date: Thu, 25 Oct 2007 13:03:21 -0400
Message-ID: <18291.1193331801@sss.pgh.pa.us> (raw)
In-Reply-To: <20071025164917.D310A9F9251@postgresql.org>
References: <20071024172620.4ECD2607787@mx1.hub.org>
<20071025164917.D310A9F9251@postgresql.org>
Steve Midgley <public@misuse.org> writes:
> select * from test_order
> order by id <> 3, email
> --sql end
> Putting the expression "id <> 3" causes the id of 3 to sort to the TOP
> of the list. This statement does the same thing:
> select * from test_order
> order by id = 3 DESC, email
> I know there is a good, rational reason for this, and I'm hoping
> someone will explain it to me?
These expressions yield boolean true or false, and false sorts before true.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, public@misuse.org
Subject: Re: (repost) Help understanding expressions in order by clause
In-Reply-To: <18291.1193331801@sss.pgh.pa.us>
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