Power BI sumif function in different table has a many to many relationship

Question

I need a function to calculation a percentage based on two values in two different tables that has many to many relationship in power BI DAX expression.

Answer 1

I assume your relations are ok, you did not give this info. I hope based on my example you can manage:

%Order = 
    var orderId = 'table'[orderID]
    var orderTotal = CALCULATE(SUM('table'[ItemValue]); FILTER('table';orderId =  'table'[orderID]))
return 'table'[ItemValue]/orderTotal