Calculate difference between current month and previous month for cumulative data

Jay92SG — Wed, 16 Aug 2023 14:41:48 GMT

Hi, i have a report that i can extract on a monthly basis.

For example,

Date Asset ID Transaction
1 Dec 2022 123 0
1 Jan 2023 123 1000
1 Feb 2023 123 1000
1 Mar 2023 123 1000

I need to get the monthly additions for Mar 2023, i will need to take the transaction for Mar23 (1000) and deduct Feb23 (1000) to get 0 additions. It would mean that for Jan23, it is $1000 addition using Jan23 (1000) - Dec22(0).

the report is a long list with many different asset ID. can anyone help me? i have tried the below but doesnt work. I am thinking i will need to summarize by asset ID first, and for each row, compute the difference by looking up to the previous month transaction.
AdditionCM = (CALCULATE( sum(ZFA0006[Transaction]) , LASTDATE(ZFA0006[Date])) )- (CALCULATE( sum(ZFA0006[Transaction]) , PREVIOUSMONTH(ZFA0006[Date])) )

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Calculate difference between current month and previous month for cumulative data