Обсуждение: a change of query

On Tue, 2003-02-25 at 14:03, James Cooper wrote:
> select distinct cp.person_id from cluster_person cp, cluster c where
> cp.cluster_id = c.cluster_id and c.c_id = 1
> 
> can this query be changed to give just the row count?( of the distinct
> rows )

select count(distinct cp.person_id) from ...

Is that what you were after?

Brad Hilton
VPOP Technologies, Inc.

On Tue, 2003-02-25 at 17:03, James Cooper wrote:
> select distinct cp.person_id from cluster_person cp, cluster c where
> cp.cluster_id = c.cluster_id and c.c_id = 1
>
> can this query be changed to give just the row count?( of the distinct
> rows )

:) So close

select count(distinct cp.person_id) from...

--
Rod Taylor <rbt@rbt.ca>

PGP Key: http://www.rbt.ca/rbtpub.asc

----- Original Message -----

From: James Cooper

To: sql

Sent: Tuesday, February 25, 2003 3:03 PM

Subject: [SQL] a change of query

select distinct cp.person_id from cluster_person cp, cluster c where cp.cluster_id = c.cluster_id and c.c_id = 1

can this query be changed to give just the row count?( of the distinct rows )

yes: i am aware of count() but this wont count the distinct rows - I can however achive this with an nested person_id in(select... etc but that slows things down big time!!!!

the above quey gives me my resultset asap - is there a way to get just the number of rows with the same speed

My thoughts are that I could just make a plpgsql  function with a GET Diagniostics ROW_COUNT -

thoughts?

 

James