From: | Thom Brown <thom(at)linux(dot)com> |
---|---|
To: | Matthew Wakeling <matthew(at)flymine(dot)org> |
Cc: | Thomas Kellerer <spam_eater(at)gmx(dot)net>, pgsql-performance(at)postgresql(dot)org |
Subject: | Re: Sorted group by |
Date: | 2010-08-10 16:28:46 |
Message-ID: | AANLkTi=yOngjw2-hhoyQ8YiUzQ7JCztWTTU_G_UWO_fb@mail.gmail.com |
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Lists: | pgsql-performance |
On 10 August 2010 17:06, Thom Brown <thom(at)linux(dot)com> wrote:
> On 10 August 2010 17:03, Matthew Wakeling <matthew(at)flymine(dot)org> wrote:
>> On Tue, 10 Aug 2010, Thomas Kellerer wrote:
>>>
>>> No. It's built in (8.4) and it's called Windowing functions:
>>> http://www.postgresql.org/docs/8.4/static/tutorial-window.html
>>> http://www.postgresql.org/docs/8.4/static/functions-window.html
>>>
>>> SELECT group, last_value(value) over(ORDER BY number)
>>> FROM table
>>
>> I may be mistaken, but as I understand it, a windowing function doesn't
>> reduce the number of rows in the results?
>>
>
> I think you are mistaken. The last_value function is a window
> function aggregate. Give it a try.
>
D'oh, no, I'm mistaken. My brain has been malfunctioning today.
--
Thom Brown
Registered Linux user: #516935
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