Re: Celko: help with an experiment

I have to agree with Joe here. Any expression within an aggregate operator invocation must be considered a pre-aggregate expression. The fact that it does not reference columns of the table being aggregated is irrelevant. To write it out explicitly:

select max(Twelve) from (select 12 as Twelve from T) as T;

Incidentally, the fact that the SQL language allows for such debates as this is a direct result of its poor design. A language in which aggregation was orthogonal to projection and extension would not suffer from these type of interpretation problems. Such a language exists (shameless plug) and is called D4. It is an 'Industrial D' as described by C. J. Date and Hugh Darwen in The Third Manifesto. Try it out at www.alphora.com.

Regards,
Bryn Rhodes
Alphora Received on Thu Jul 11 2002 - 11:14:43 CDT