At 24/02/2002 10:36 AM, you wrote:

>I can see that sometimes you might want it to behave like this. But
>there would be plenty of simple methods to achieve the same without
>Sum returning Null. On the other hand, not being able to embed a sum
>query into anything, and not being able to include the result in a
>calculation, is a serious limitation, and the alternatives can be
>very long winded. Often you have to write a procedure to return a
>result set, when a single query would do if sum was useable.
>
>It really makes very little difference whether I am criticising Ib,
>or Firebird, or the SQL standard. The actual behaviour is
>unintuitive and illogical, and very incovenient.
>

Just to add to Claudio's explainations. I checked with MS-SQL 7 and 2000,
and they do the same thing as IB and FB. And, my guess would be that even
Oracle operates the same way as well.


Daniel Rail
Senior System Engineer
ACCRA Group Inc. (www.accra.ca)
ACCRA Med Software Inc. (www.accramed.ca)