Re: Examples of SQL anomalies?
From: Brian Selzer <brian_at_selzer-software.com>
Date: Fri, 4 Jul 2008 23:25:27 -0400
Message-ID: <HQBbk.14536$N87.10474_at_nlpi068.nbdc.sbc.com>
Date: Fri, 4 Jul 2008 23:25:27 -0400
Message-ID: <HQBbk.14536$N87.10474_at_nlpi068.nbdc.sbc.com>
"Marshall" <marshall.spight_at_gmail.com> wrote in message
news:6ad51b62-e66a-4daa-b21c-c361fd6b22f8_at_8g2000hse.googlegroups.com...
> What can be meaningfully asked is determined by the schema.
>
> If the schema specifies that the weight attribute is nullable,
> then the question of how much a shipment weighs in total
> is a question that cannot be asked.
>
>
> Marshall
I would agree except that in the exceptional case where all of the weights have been supplied, the question can be answered. That's why I would return NULL for SUM except in such execptional cases. That way you get an indeterminate result exactly when the result cannot be determined. Received on Sat Jul 05 2008 - 05:25:27 CEST