I need to design a query which calculates the variance of costs with respect to the previous month. I want to select a fiscal period range and only show the variances for these selected periods. However when I enter a range the calculations for the first period dont work. Also If I add the fiscal period characteristic over the structure the formulas are not calculated for the previous period.
How can I calculate the variance of costs with respect to previous months and display them monthly?
Thanx a lot in advance,