3647 NULL may not be used as the argument for an aggregate function.
Explanation:
It is not legal to request the MIN, MAX, AVG, SUM, or COUNT of NULL.
Generated By:
OPT modules.
For Whom:
The End User.
Remedy:
User has entered a query that is not allowed. The aggregate function referencing NULL should be removed from the query. Then the query can be resubmitted.