Re: Celko: help with an experiment
From: --CELKO-- <71062.1056_at_compuserve.com>
Date: 7 Jul 2002 12:14:00 -0700
Message-ID: <c0d87ec0.0207071114.33e775ba_at_posting.google.com>
Date: 7 Jul 2002 12:14:00 -0700
Message-ID: <c0d87ec0.0207071114.33e775ba_at_posting.google.com>
>> What are the "correct" answers? <<
I don't think there is one!
The problem is that COUNT(*) is a set level function -- Cardinality -- in which an empty set returns a zero. But the other aggregate and scalar functions in SQL work inside the set, so cannot return anything from an empty set. It's G. Cantor's thing about "set as a whole" versus "set as a collection of elments" showing up in the real world.
I have sent this to the INCITS H2 Committee and Don Deutsch has spread it around, so we will have to see what happens ... Received on Sun Jul 07 2002 - 21:14:00 CEST