Re: Counting all results before LIMIT - Mailing list pgsql-general

From Mike Christensen
Subject Re: Counting all results before LIMIT
Date
Msg-id CABs1bs07p6UB3oV=Da3C7+SEB80WnEyHkEAOJ9G6t4m4Syj4pw@mail.gmail.com
Whole thread Raw
In response to Re: Counting all results before LIMIT  (P Gouv <kadmos@gmail.com>)
Responses Re: Counting all results before LIMIT
List pgsql-general
You could use a windowing function.  Something like:

SELECT x, y, z, COUNT(*) OVER()
FROM Foo
LIMIT 50;

On Fri, Oct 5, 2012 at 8:02 AM, P Gouv <kadmos@gmail.com> wrote:
You cant. There is an article about count performance. Generally its slow but latest version 9.2 i think supports index for count under some condition.But 300 isnt that much that you should worry.Another modern solution is to not count results just add one more at limit to see if there is next page.


On Fri, Oct 5, 2012 at 5:29 PM, Moshe Jacobson <moshe@neadwerx.com> wrote:
We have a PHP web application that pulls results from the database and paginates them.
We show e.g. "1-50 of 300" so the user knows how many total results there are, and which ones are currently being displayed.
To achieve this, we use a query with LIMIT...OFFSET to get the displayed results, and we do another identical query using count(*) to get the total count.
Is there a more efficient way to do this that does not require us to do two queries? I just feel that it's a waste of resources the way we do it.

Thanks!

--
Moshe Jacobson
Nead Werx, Inc. | Senior Systems Engineer
2323 Cumberland Parkway, Suite 201 | Atlanta, GA 30339
moshe@neadwerx.com | 
www.neadwerx.com



pgsql-general by date:

Previous
From: P Gouv
Date:
Subject: Re: Counting all results before LIMIT
Next
From: Ivan Voras
Date:
Subject: Re: Re: What's faster? BEGIN ... EXCEPTION or CREATE TEMP TABLE IF NOT EXISTS?