From: Theo Kramer <theo@flame.co.za>
To: pgsql-performance@postgresql.org
Subject: Re: Multicolumn order by
Date: Wed, 19 Apr 2006 08:00:39 +0200
Message-ID: <1145426438.3048.25.camel@josh> (raw)
In-Reply-To: <19819.1145401713@sss.pgh.pa.us>
References: <1145398075.3048.18.camel@josh>
<19819.1145401713@sss.pgh.pa.us>
On Wed, 2006-04-19 at 01:08, Tom Lane wrote:
> 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
That is awesome - been fighting with porting my isam based stuff onto
sql for a long time and the row comparison operator is exactly what I
have been looking for.
I tried this on my test system running 8.1.3 and appears to work fine.
Appreciate it if you could let me know in what cases it does not work
properly.
--
Regards
Theo
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To: pgsql-performance@postgresql.org
Cc: theo@flame.co.za
Subject: Re: Multicolumn order by
In-Reply-To: <1145426438.3048.25.camel@josh>
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