Re: How to re-sort a sorted query?

From: Oliver Elphick <olly(at)lfix(dot)co(dot)uk>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Yudie <yudie(at)axiontech(dot)com>, pgsql-sql(at)postgresql(dot)org
Subject: Re: How to re-sort a sorted query?
Date: 2004-10-26 21:57:53
Message-ID: 1098827873.2414.47.camel@linda
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-sql

On Tue, 2004-10-26 at 17:43 -0400, Tom Lane wrote:
> Oliver Elphick <olly(at)lfix(dot)co(dot)uk> writes:
> > On Tue, 2004-10-26 at 14:23 -0500, Yudie wrote:
> >> Then I do this query to get unique store number and also the cheapest
> >> price from each store:
> >>
> >> SQL= "Select distinct on (storenumber), itemsku, storenumber,price
> >> from storeproduct where itemsku='10001'
> >> order by storenumber, price"
>
> > That won't get you the cheapest price,
>
> Sure it will. It's a perfectly good application of DISTINCT ON.
> However, he has to use that particular ORDER BY to get the answers
> he wants.

Ah - because ORDER BY is applied before DISTINCT ON; I hadn't realised
that.

--
Oliver Elphick olly(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
GPG: 1024D/A54310EA 92C8 39E7 280E 3631 3F0E 1EC0 5664 7A2F A543 10EA
========================================
"Whosoever therefore shall be ashamed of me and of my
words in this adulterous and sinful generation; of him
also shall the Son of man be ashamed, when he cometh
in the glory of his Father with the holy angels."
Mark 8:38

In response to

Browse pgsql-sql by date

  From Date Subject
Next Message Scott Pederick 2004-10-27 11:02:35 JOIN not being calculated correctly
Previous Message Tom Lane 2004-10-26 21:43:41 Re: How to re-sort a sorted query?