How can I sum data on a rolling 12 months
I have a customer who would like a report showing a rolling 12 months consumption but with each month showing the total of the previous 12 months i.e. Oct 18- Sept 19, Nov 18 - Oct 19 etc.
The report for the rolling 12 months has been created (see below) showing the consumption for each month but I am struggling to work out how to sum the previous 12 months on a rolling basis. Please could you advise if this is even possible and if so, how it could be done.
Any help would be appreciated.