Using an aggregate function in where

Question

I saw a few threads here with similar questions however I couldn\'t find something fitting my needs.

Consider the following table and example data:

CRE         


        

Answer 1

You can't use aggregate expression in the where clause - this is what the having clause is for:

SELECT   a, SUM(b)
FROM     foo
GROUP BY a
HAVING   SUM(b) > 9