Sum the last twelve months

[#1]

Hi,

I feel this should be straight forward however I'm struggling to get the last twelve months of sales when I select a period. If I select period 2012/1 I want the sum of sales from 2011/2 to 2012/1.  I've attached a sample data; any guidance would be appreciated.

In the greater context I'm need to calculate Creditor Days so I'm looking to incoprate the formula for the last twelve months of purchases into another formula.

Thanks in advnace.

C

[kumarnatarajan]

Hi,

First change the period format then try the below syntex

EX: =Sum({$<Period={"<=$(=Max(Period)) >=$(=AddMonths(Max(Period),-11))"}>}Amount) 

Find the attached file