From: | Chris <dmagick(at)gmail(dot)com> |
---|---|
To: | Ray Bannon <bannonr(at)comcast(dot)net> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Union Query Improvement |
Date: | 2007-02-14 07:25:41 |
Message-ID: | 45D2B975.5020501@gmail.com |
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Thread: | |
Lists: | pgsql-general |
Ray Bannon wrote:
> I have a query which is running a bit slowly, and I'm wondering if anyone
> has a design improvement. Basically it's a series of unions as follows:
>
> Select ID, plan_name from table/view
> Where plan_name = 'A'
> And rownum = 1
> UNION
> Select ID, plan_name from table/view
> Where plan_name = 'B'
> And rownum = 1
> UNION
> Select ID, plan_name from table/view
> Where plan_name = 'C'
> And rownum = 1
> UNION
>
> Ad infinitum for about 100 iterations.
I'm sure I'm missing something but wouldn't this give the same results:
select id, plan_name from table where rownum=1 and plan_name in ('A',
'B', 'C');
?
Or do the rownum's change later on?
--
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