I've got a question. I have data about the sales for different salesmen and time time periods. I want to find the difference between the sales of different salesmen from their last month and previous. The problems are that date in format DDMMYYYY (and I should use Month(Date)-function) and that different salesmen have different last monthes (I should use Max()-functions). And when I tried to do that via the Diagram, I have the error because in the case of the Diagram there is only one operation of aggrecation may be used. Is it really to perform such caclulations via the Diagram? P.S. I'm a beginner and sorry if the qestion isn't correct.
