From: Tom Lane <tgl@sss.pgh.pa.us>
To: theo@flame.co.za
Cc: pgsql-performance@postgresql.org
Subject: Re: Multicolumn order by
Date: Tue, 18 Apr 2006 19:08:33 -0400
Message-ID: <19819.1145401713@sss.pgh.pa.us> (raw)
In-Reply-To: <1145398075.3048.18.camel@josh>
References: <1145398075.3048.18.camel@josh>
Theo Kramer <theo@flame.co.za> writes:
> select * from mytable where
> (c1 = 'c1v' and c2 = 'c2v' and c3 >= 'c3v') or
> (c1 = 'c1v' and c2 > 'c2v') or
> (c1 > 'c1v')
> order by c1, c2, c3;
Yeah ... what you really want is the SQL-spec row comparison operator
select ... where (c1,c2,c3) >= ('c1v','c2v','c3v') order by c1,c2,c3;
This does not work properly in any current PG release :-( but it does
work and is optimized well in CVS HEAD. See eg this thread
http://archives.postgresql.org/pgsql-hackers/2006-02/msg00209.php
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, theo@flame.co.za
Subject: Re: Multicolumn order by
In-Reply-To: <19819.1145401713@sss.pgh.pa.us>
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