From: | Bruno Wolff III <bruno(at)wolff(dot)to> |
---|---|
To: | Gary Stainburn <gary(dot)stainburn(at)ringways(dot)co(dot)uk> |
Cc: | pgsql-sql(at)postgresql(dot)org |
Subject: | Re: select best price |
Date: | 2005-10-26 18:40:02 |
Message-ID: | 20051026184002.GI11447@wolff.to |
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Thread: | |
Lists: | pgsql-sql |
On Wed, Oct 26, 2005 at 16:38:48 +0100,
Gary Stainburn <gary(dot)stainburn(at)ringways(dot)co(dot)uk> wrote:
> On Wednesday 26 October 2005 4:21 pm, Gary Stainburn wrote:
> > Hi folks
> >
> > I've got a table holding item code(cs_id), supplier a/c (co_id) , and
> > price (cs_price).
> >
> > How can I select the rows containing the lowest price for each item
> > code?
> >
> > I've tried various forms of min() etc and know it must be simple but
> > I'm stumped.
> >
> > Gary
>
> I've come up with the select below. Is there a better/more efficient
> way of doing this?
>
> select cp.cs_id, from cons_price_details cp,
> (select cs_id, min(cs_price) as cs_price
> from cons_price_details
> group by cs_id
> ) v
> where cp.cs_id = v.cs_id and cp.cs_price = v.cs_price;
If you only need one lowest price entry where there are ties, you could also
use DISTINCT ON (a nonstandard Postgres extension) and ORDER BY that may
execute faster.
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