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select best price
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* select best price
@ 2005-10-26 15:21  Gary Stainburn <gary.stainburn@ringways.co.uk>
  0 siblings, 1 reply; 3+ messages in thread

From: Gary Stainburn @ 2005-10-26 15:21 UTC (permalink / raw)
  To: pgsql-sql

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
-- 
Gary Stainburn
 
This email does not contain private or confidential material as it
may be snooped on by interested government parties for unknown
and undisclosed purposes - Regulation of Investigatory Powers Act, 2000     




^ permalink  raw  reply  [nested|flat] 3+ messages in thread

* Re: select best price
@ 2005-10-26 15:38  Gary Stainburn <gary.stainburn@ringways.co.uk>
  parent: Gary Stainburn <gary.stainburn@ringways.co.uk>
  0 siblings, 1 reply; 3+ messages in thread

From: Gary Stainburn @ 2005-10-26 15:38 UTC (permalink / raw)
  To: pgsql-sql

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;

-- 
Gary Stainburn
 
This email does not contain private or confidential material as it
may be snooped on by interested government parties for unknown
and undisclosed purposes - Regulation of Investigatory Powers Act, 2000     




^ permalink  raw  reply  [nested|flat] 3+ messages in thread

* Re: select best price
@ 2005-10-26 18:40  Bruno Wolff III <bruno@wolff.to>
  parent: Gary Stainburn <gary.stainburn@ringways.co.uk>
  0 siblings, 0 replies; 3+ messages in thread

From: Bruno Wolff III @ 2005-10-26 18:40 UTC (permalink / raw)
  To: Gary Stainburn <gary.stainburn@ringways.co.uk>; +Cc: pgsql-sql

On Wed, Oct 26, 2005 at 16:38:48 +0100,
  Gary Stainburn <gary.stainburn@ringways.co.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.



^ permalink  raw  reply  [nested|flat] 3+ messages in thread

end of thread, other threads:[~2005-10-26 18:40 UTC | newest]

Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2005-10-26 15:21 select best price Gary Stainburn <gary.stainburn@ringways.co.uk>
2005-10-26 15:38 ` Gary Stainburn <gary.stainburn@ringways.co.uk>
2005-10-26 18:40   ` Bruno Wolff III <bruno@wolff.to>

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