From: Bruno Wolff III <bruno@wolff.to>
To: PFC <lists@boutiquenumerique.com>
Cc: Kenneth Gonsalves <lawgon@thenilgiris.com>
Cc: Ramakrishnan Muralidharan <ramakrishnanm@pervasive-postgres.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: two sums in one query
Date: Fri, 8 Jul 2005 10:55:50 -0500
Message-ID: <20050708155550.GA28683@wolff.to> (raw)
In-Reply-To: <op.stlng6uhth1vuj@localhost>
References: <02767D4600E59A4487233B23AEF5C5992A4093@blrmail1.aus.pervasive.com>
<200507081306.08597.lawgon@thenilgiris.com>
<op.stlkoiq4th1vuj@localhost>
<20050708140725.GA22725@wolff.to>
<op.stlng6uhth1vuj@localhost>
On Fri, Jul 08, 2005 at 16:49:44 +0200,
PFC <lists@boutiquenumerique.com> wrote:
>
> >>SELECT (SELECT sum(amount) FROM table WHERE debit=X) AS debit, (SELECT
> >>sum(amount) FROM table WHERE credit=x) AS credit;
> >
> >If most of the records are credits or debits you don't want to do this.
> >A single sequential scan through the table will be the best plan.
>
> I thought that debit = source account # and credit = dest account #,
> and there are a lot of different account...
You aren't likely to see a significant speed up in that case either.
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To: pgsql-sql@postgresql.org
Cc: bruno@wolff.to, lists@boutiquenumerique.com, lawgon@thenilgiris.com, ramakrishnanm@pervasive-postgres.com
Subject: Re: two sums in one query
In-Reply-To: <20050708155550.GA28683@wolff.to>
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