Re: count and limit

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От Michael Fuhr
Тема Re: count and limit
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Msg-id 20060818004932.GA93594@winnie.fuhr.org
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Ответ на Re: count and limit  (Chris <dmagick@gmail.com>)
Ответы Re: count and limit  (Chris <dmagick@gmail.com>)
Список pgsql-general
On Fri, Aug 18, 2006 at 10:34:44AM +1000, Chris wrote:
> Fabio Victora Hecht wrote:
> >I was wondering if there's a way to count the results of a query and
> >return part of the result set it in one query (LIMIT). Because I usually
> >have to count the results using one query (to tell the user how many
> >records match the criteria) and show the first 20 records.
>
> I was going to suggest a cursor but I don't think you can get the number
> of results a cursor has :(

You can but you have to MOVE to the end, so the backend has to visit
each tuple just as it would for COUNT.  I answered a similar question
recently:

http://archives.postgresql.org/pgsql-novice/2006-07/msg00220.php

--
Michael Fuhr

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