Transforming Cumulative data files

[Neo777]

Hello guys, 

I need help in transforming the data based on the example I attached. I am receiving monthly data, but these data contain cumulative values for the period (no data column per month). As you see in the attached picture I have two files one is the January - August file and the second one is the January - September file. So if I need to calculate the values of any KPIs for the company "z" I need to use the correct file (the latest data - Jan-Sept) and subtract the values from the same company from the previous file (Jan - August) and to assign that value as a September data (9/2023) in the new column to have a correct data type (who will be in relationship with my Calendar dimension table). So, for Octobar data, I will receive the Octobar file (from January to October) and the same process of subtracting the value of the previous file in this case Jan - Sept file. Do you know how I can transform that in Power Query or using some DAX measure?

[Neo777]

This is just an example of how my data are structured. I do not have permission to change anything on the source but I can make changes in the PBI Query Editor. I already created a date table but still, these are cumulative values. I created some DAX measures but still, this is not the solution I expected 

[Ashish_Mathur]

A date column will have to somehow be created for the subtraction to happen.  Share data (with actual column headers) in a format that can be pasted in an MS Excel file.

[Ashish_Mathur · Accepted solution]

Hi,

There has to be a Date column in each table.  Creae that and share data in a format that can be pasted in an MS Excel file.