GROUPBY_WHERE summarizes across specific rows of data within a group. The output of this function is a single column. The output is the result of the operation specified by
keyword on the
rolled_field over the homogeneous group specified by the
group_field, filtered by the
where_value. Only rows with a
where_value of one are included in the calculation.
If the optional output_field is not supplied, then the result is the result of the operation on
rolled_field. If
output_field is supplied, then the result is the
output_field of the row within the group.