Re: Phantom record problem.

From: nronayette <r97m10(at)socotec(dot)fr>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: Phantom record problem.
Date: 2000-06-26 20:16:33
Message-ID: 3957BA21.7AE2DDFE@socotec.fr
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hi
I don't think so. Because there is a difference between a sum where the result
is equal to zero (for example 1+2-3 =0 or 0+0 =0 ) and a sum of row that does
not exist (here where the uid = 5). With this sum, the row return is null but
the result exist (1 row) because the sum is done.

i hope i was clear...

"Poul L. Christiansen" a écrit :

> I think that is suppose to happen when no records are returned.
>
> But I must admit that it would be more meaningful, to return a 0 instead of
> an empty string.

>
>
> Poul L. Christiansen
>
> Richard wrote:
>
> > I am experiencing a problem whereby when I submit a query containing an
> > aggregate, and if the WHERE clause is not satisfied, I receive a result
> > of "(1 row)", but that row is blank.
> >
> > Here is an example:
> >
> > Table 1: Customers
> >
> > Name | UID
> > ----------------------
> > Andrews | 1
> > Smith | 2
> > Jones | 3
> > Baker | 4
> >
> > Table 2: Deposits
> >
> > UID | Amount
> > ----------------------
> > 3 | 7.00
> > 1 | 15.00
> > 1 | 10.00
> > 2 | 8.00
> > 3 | 20.00
> >
> > Now, if I submit the following query:
> >
> > SELECT name, sum(amount)
> > FROM customers c, deposits d
> > WHERE c.uid = d.uid and c.uid = 3
> > GROUP BY name;
> >
> > I get back:
> >
> > name | sum
> > --------------------
> > Jones | 27.00
> > (1 row)
> >
> > Fine, this looks good.
> >
> > BUT, if I submit the following query:
> >
> > SELECT name, sum(amount)
> > FROM customers c, deposits d
> > WHERE c.uid = d.uid and c.uid = 5
> > GROUP BY name;
> >
> > (note that there is no record where c.uid=5) I would not expect any rows
> > back. However, I get:
> >
> > name | sum
> > --------------------
> > |
> > (1 row)
> >
> > Is this a bug, or is it supposed to work this way? I've tried this on
> > both versions 6.5.2 and 6.5.3 with the same result.
> >
> > Any insight would be appreciated. Thank-you.
> >
> > Cheers,
> > Richard

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