Aggregation functions
So far, we have introduced two functions into our report:
ProductCounter: This performs a cumulative count on the rows in the Details section. This function belongs to the Running category.SumQty: This performs a cumulative count on the sum_amount fields of the rows present in the Details section. This function also belongs to the Running category.
Every function in the Running category performs calculations, sum, counts, and so on in a cumulative fashion, that is, they take into consideration the values obtained on previous pages. For example, the Count function appearing on the first page performs a count of the rows of the said page, from the second page on it will add the current page count to the total count of the previous one. In the same way, the functions Maximum and Minimum, when applied to the first page only take into consideration the minimum and maximum values, respectively, as shown on the first page. In the following pages, they will only update these...
