How to substract two values from two tables (many to many) by using Dax

[JPY]

Hi all,

I have two tables with many to many relationship. 

One is actualized numbers, broken down by equipment and month (table a column a) and the other one is forecast number (table b column b) with the same breakdown.

I want to create a measure to subtract columns a and b. It needs to be able to drill down by equipment level.

Does anyone know how should I go about doing it?

I tried to write something like below, but it doesn't work. I guess is because of the many to many relationship..

Calculate(Sum('table a'column a) - Sum('table b' column b)) 

Thanks

JPY

[amitchandak]

@JPY , create a bridge table /common dimension table like equipment. date and analyze against them

https://www.seerinteractive.com/blog/join-many-many-power-bi/

Can you share sample data and sample output in table format? Or a sample pbix after removing sensitive data.