Re: ORDER BY and LIMIT with SubSelects

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: Ron St-Pierre <rstpierre(at)syscor(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: ORDER BY and LIMIT with SubSelects
Date: 2004-01-21 18:36:56
Message-ID: 20040121183656.GC11684@wolff.to
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On Wed, Jan 21, 2004 at 09:18:18 -0800,
Ron St-Pierre <rstpierre(at)syscor(dot)com> wrote:
>
> My question is in regards to steps 2 and 3 above. Is there some way that
> I can combine both steps into one to save some time?

TIP 4: Don't 'kill -9' the postmaster
SELECT SS.* FROM
(SELECT DISTINCT ON (nonUniqField)
first, second, third, cost, payDate, nonUniqField
FROM histdata
WHERE userID = 19048 AND cost IS NOT NULL
ORDER BY nonUniqField, payDate DESC LIMIT 200
)
SS
ORDER BY payDate;

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