As I was working on a new Report, I had two fields with computations.
These are easy to handle, for example, for a Total you write something like this:
And you get a product of the quantity and the price.
That works great. At first I had a very simple query and it looked like there was a problem in computed field, but I still decided to first add the WHERE clause to allow the user to limit the data to a given set of dates:
WHERE (((Invoice.CreatedDate)>=[Enter start date:])
AND ((Invoice.CreatedDate)<=[Enter end date:]))
Notice all the parenthesis. Also ...