24 Month Sales file Adding new months sales and removing duplicate months to historic sales file

[ToffeeMark]

Hi, 

I receive every month a 24 month sales file which is always being corrected so best to use the most recent data.

Each month the new month is added and the oldest month deleted.   The new file starts september 17. 

How do I append the newest file to a table and replace the months that are already in it but keep the older non duplicate months?

e.g. I have an old master file which starts Jan 17.  so can I automate it so that I add Sep 17 onwards to this file and overwrite/delete any duplicate months in the master file? (I want to build a longer time frame).

Next month add Oct 17 onwards and so on (obviously my table will increase to 25,26 months etc)

[v-frfei-msft]

Hi @ToffeeMark ,

Hope this case can help you.

https://community.powerbi.com/t5/Desktop/store-historical-data-from-Power-BI-Online/m-p/128189#M5444...

[ToffeeMark]

bably just going to manually filter the old Master table Jan - Aug 17 then append them to the new file....