Consider a fact table in an OLAP application: Facts (D1, D2, val), where D1 and D2 are its dimension attributes and val is a dependent attribute. Suppose

attribute D1 takes 3 values and D2 takes 2 values, and all combinations of these values are present in the table Facts. How many tuples are there in the result of the following query?

SELECT D1, D2, sum(val)

FROM Facts

GROUP BY CUBE (D1, D2);