Calculate the gains since the start date

[laff12]

Hi, 

I have a problem that I can't crack. I want to calculate the gains of a cable company. I have 2 tables. First table, "Calendar" stores the unique dates. The second table "Agreements" stores the information about the agreements:

• Agreement column is a unique identifier of a contract
• StartDate is a date when an agreement was signed
• MonthlySubscription is a monthly fee that client pays to a company
• ServiceFee is a one time gain for the company (generated in a month when agreement was signed

So each customer generates MonthlySubsctiption + ServiceFee as a revenue for the company in the first month and a MonthlySubscription in each subsequent month. I tried to create a measure that would generate the results similar to the one that I presented on a picture below in "Expected Result" table. Please note that even though I presented "Expected Result" as a table in fact measure should generate a scalar value for a specific date. Another useful information is that there is a one to many relationship between the Calender and Agreements (Date - StartDate).

[laff12 · Accepted solution]

This pretty much solves the problem:
https://community.powerbi.com/t5/Desktop/DAX-Calculate-sum-of-DateDiffs-between-last-date-of-slicer-...