How to calculate measure based on previous date

[rbustamante]

Hi all.

In excel there is a feature to calculate or show the values in a Pivot Table based on the difference of the previous record. I show the option:

I'm trying to do this in DAX but it doesn't run ok. I have a table with the amounts of products at a given date and the product name. I made the following measure:

mDifference =

VAR _ThisMonth =

CALCULATE ( SUM ( 'Products (2)'[Amount] ) )

VAR _PreviousMonth =

CALCULATE ( SUM ( 'Products (2)'[Amount] ), PREVIOUSMONTH ( 'Date'[Date] ) )

RETURN

_ThisMonth - _PreviousMonth

Always return 0.

In the model I've defined a Date Table

Here is the pbix file

https://we.tl/t-xaf4zegkBd

Please, anyone can help me

[Payeras_BI · Accepted solution]

Hi @rbustamante ,

For non contiguous months try this one:

mDifference = 
VAR _CurrentDate =
    SELECTEDVALUE ( 'Products (2)'[Date])
VAR _PreviousDate =
    CALCULATE (
        MAX ( 'Products (2)'[Date] ),
        ALLSELECTED ( 'Products (2)'[Date] ),
        KEEPFILTERS ( 'Products (2)'[Date] < _CurrentDate )
    )
VAR _ThisMonth =
    CALCULATE ( SUM ( 'Products (2)'[Amount] ) )
VAR _PreviousMonth =
    CALCULATE (
        SUM ( 'Products (2)'[Amount] ),
        'Products (2)'[Date] = _PreviousDate
    )
RETURN
    _ThisMonth - _PreviousMonth

Regards,

[CNENFRNL]

@rbustamante , you might want to try

mDifference = 
VAR _ThisMonth = CALCULATE ( SUM ( 'Products (2)'[Amount] ) )
VAR _PreviousMonth = CALCULATE ( SUM ( 'Products (2)'[Amount] ), PREVIOUSMONTH ( 'Products (2)'[Date] ) )
RETURN
    _ThisMonth - _PreviousMonth

[rbustamante]

Thanks for the response, but doesn't work if I choose  non contiguous dates, for example 11/30/2020 and 12/31/2019