4. The method as claimed in claim 3 , wherein identifying an aggregate group comprises: determining the type of the aggregate; when the aggregate is a report aggregate having a standard aggregate counterpart, deriving the aggregate group based on a FOR clause of the aggregate; and when the aggregate is a non-report aggregate, deriving the aggregate group based on an AT clause of the aggregate.
3. The method as claimed in claim 1 , wherein analyzing the filter condition to determine the filter group comprises: identifying aggregates of the filter condition; for each identified aggregate, identifying an aggregate group of the aggregate, the aggregate group comprising a list of expressions over which the aggregate is computed; and selecting the aggregate group with the lowest level of granularity as the filter group.