18 May
2006
18 May
'06
2:14 p.m.
[...] A small detail of SQL spec that might be relevant: If a column contains only NULL or no values at all the result of the aggregate function is NULL. COUNT is an exception, obviously.
Yes, I think it is relevant. Because the semantics of SUM are as is, a SQL query can tell an all-NULL column (yields NULL) from an empty aggregation input set (yields 0). I vote for the status quo.
Cheers, --Teggy -- | Prof. Dr. Torsten Grust grust@in.tum.de | | http://www-db.in.tum.de/~grust/ | | Database Systems - Technische Universität München (Germany) |