How to get previous month data with ID to ID relationship

[AriBnK]

Hello everyone,

I have two tables :

- DIM_Period which is a date table, containing [ID_Period] (integer), [Period] (text) and [Date] (date)

- FACT_Table wich is the tbale where my values are stored, containing [ID_Period] (integer) and [Value] (integer)

I am trying to display in a visual the sum of value for current month and for previous month for a selected period, like this :

But in order to reduce report size, I mapped the DIM_Period table to my FACT_Table with IDs of integer type (because integer type is less size consuming than date type).

So my relationship looks like this :

And here is my problem : I can't find a way to use PREVIOUSMONTH or DATEADD correctly with that case.
I created a mesaure like this :

PreviousMonth = CALCULATE(SUM(FACT_Table[Value]), PREVIOUSMONTH(DIM_Period[Date]))

But the result of the measure was blank in the table :

Does someone can help me with that problem ?

I would like to continue mapping the DIM & FACT tables with ID relationship

Thank you

[speedramps · Accepted solution]

It is best practice to use calendar "offsets"

Learn about "offsets" here Click here for Offset tutorial video 

Thanks for the clear description of the problem with example data. I wish everyone did that!

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