Trouble with creating a certain measure

Hi Anonymous ,

You can refer the following links to get the different between new discount and old discount. 

Solved: Calculate difference from previous month - Microsoft Fabric Community

difference=
sum(DW_Data_Salg[Inntekt])-CALCULATE(SUM(DW_Data_Salg[Inntekt]),PREVIOUSMONTH(DW_Data_Salg[DATO].[Date]))

Solved: Dax for Current Month & Previous Month - Microsoft Fabric Community

Solved: Current Month vs Previous Month - Microsoft Fabric Community 

If the above ones can't help you get the expected result, please provide some raw data (exclude sensitive data) with Text format in your tables and your expected result. It would be helpful to find out the solution. You can refer the following link to share the required info:

How to provide sample data in the Power BI Forum

And It is better if you can share a simplified pbix file. You can refer the following link to upload the file to the community. Thank you.

How to upload PBI in Community

Best Regards