Calculate the difference of two fields from two different spreadsheets

[aiplbonn]

Hey,
I am brand new to PowerBI and have a question.
I have an XLS file with two sheets, DATA and VOUCHER, which I load into Power BI.
Each of these sheets contains the year, month, partner and a sales value.
For DATA it is the turnover and for VOUCHER the voucher value.
In Power BI I have built something where I can select a partner for DATA, a month and year and then get the total turnover.
I have built the same for VOUCHER. I choose a partner, a month and a year and then I get the sum of the vouchers for this month.
Now of course I would like to have the real turnover, i.e. turnover minus voucher value.
How do I do this with Powerbi? I know how to do it with xls but I would like to do it with PowerBI.
Attached are screenshots of it.

I hope you can help me and my question is not too wrong.

[johnt75 · Accepted solution]

Create a dimension table which has all your partners in it, like

Partners =
DISTINCT (
    UNION ( DISTINCT ( 'Data'[Partner] ), DISTINCT ( 'Voucher'[Partner] ) )
)

and create a one-to-many relationship from this new table to both Data and Voucher. Also create a date table, marked as a date table, and link that to both Data and Voucher.

You can then create a simple measure like

Total Revenue =
SUM ( 'Data'[Revenue] ) - SUM ( 'Voucher'[Voucher Revenue] )

and put that in visuals with columns from your Date and Partners tables.