subtract a value if in another column a second id with an .W exist

[ElectricalGuy]

Hi everybody,

thank you very much for the quick help at the first step. (Solved: automatically subtract by an additinal letter - Microsoft Power BI Community) Unfortunately the solution for my issue needs a further step. I need to subtract the value out of the row "Vorgangssumme" as you can see at the picture. The formula would be:

If a seconde id with ".W" exist than subtract the value of "Vorgangssumme" from the row with the ´".W" from the value from the row without the ".W", as you can see in the picture below. Otherwise show the value without the subtraction.

I hope that my explanations is comprehensible.

[Ahmedx · Accepted solution]

1) need to create an index column

2) write the following measure:

[ElectricalGuy]

Thank you very much, your solution works. Now i have a new issue but this time based on the data. 

[lbendlin]

Please provide sample data that covers your issue or question completely, in a usable format (not as a screenshot).
https://community.powerbi.com/t5/Community-Blog/How-to-provide-sample-data-in-the-Power-BI-Forum/ba-...
Please show the expected outcome based on the sample data you provided.

https://community.powerbi.com/t5/Desktop/How-to-Get-Your-Question-Answered-Quickly/m-p/1447523