Like the counting function, when several aggregations with grouping keys are used in a rule, the group and count operations must be cascaded as shown in figure 14.

But if you use multiple aggregations with the same grouping keys, or multiple counting functions that count the same column, it will not significantly increase the execution time of the rule.

Similarly, there is also a rule for counting the expenses made by the firm. Expenses are not counted unless the amount of expense is actually paid by the company.