Subtract two columns with Many to Many Relationship - Likely Measure

Hi USABB_Data -you could create a bridge table with distinct Item # if needed, but that depends on your data structure. one more, If you are working on large datasets, it's crucial to avoid calculated columns or using RELATED in a many-to-many scenario, as it can lead to performance degradation.

Instead, keep calculations in measures to allow DAX to perform calculations dynamically based on filters.

Below is the measure for example:

Price Match Discount Measure =
IF (
ISFILTERED('Discount'[Discount Name]), 
CALCULATE(
IF (
ABS(SUM('Sales Detail'[Price]) - SUM('Discount'[Item_Price])) < 0.01, 
"Y", 
"N" 
),
FILTER(
'Sales Detail',
'Sales Detail'[Item #] IN VALUES('Discount'[Item #])
)
),
BLANK() 
)

Hope this helps