[Monetdb-developers] semantics of aggregation operations
torsten.grust at gmail.com
Thu May 18 16:14:08 CEST 2006
> 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.
| Prof. Dr. Torsten Grust grust at in.tum.de |
| http://www-db.in.tum.de/~grust/ |
| Database Systems - Technische Universität München (Germany) |
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