Appending sales data to build 24 month report from a report that only shows moving 13 months
I receive a sales report from a wholesaler covering 13 months. Currently the report shows Dec 2020; Jan 2021, Feb 2021 all the way to the current month Jan 2022. Once Jan 2022 is actualised, Dec 2020 will drop off from the report adding Feb 2022 and so on.
I have built a dashboard which is working perfectly for the 13 months BUT I would like to extent the historical view to 24 month. I would like to keep the Dec 2020 sales onwards which the report drops off as we move through 2022.
The yellow highlighted column updates each week. Then on the first of every month, this column actualises for the full month and the last column in the report (in this case Dec 2020) drops off...giving the 13 months view. I want to keep the last column. I'm thinking that I will need to keep the old reports on file to keep the months that will drop off but then I will have 26 source files. But can't see any other workaround as the original report will always only be 13 month.
The data is transformed into three separate reports by unpivoting it.
This is the Sales table with the dates now running vertically as I unpivot the source table.