Help on measure to get total of last day of last month

[m9820441]

Hello, 

This is my first post, I read already a lot, but still fighting with measure. 

Situation : 

I have a table with aggregated values per day. 

2020-12-31   5

2022-01-01   10

2022-01-02   50

.

2022-01-31  100

2022-02-28   150

2022-03-31   180

What I need is a graph that shows the difference of each last day of the month compared with the last day of month before

So it should return

2022-01-31   95   (difference between 2021-12-31 and 2022-01-31)

2022-02-28   50   (difference between 2022-01-31 and 2022-02-28)

I tried with dateadd but I'm now able to find. also parallelperiod is giving me too much as I'm not interested in the sum of all values of last month, but ony value of last day of last month . 

Anyhow, solution is probably simple but I'm a bit stuck ... 

[Greg_Deckler]

@m9820441 Use EOMONTH( <some date>, -1) function to return the end of the previous month's date.

[m9820441]

Hi Greg, thx for your help already. 

I know the function, and seems I have all the pieces but I'd like some more guidance : 

This is what I tried : 

ValueMonth-1 =

 CALCULATE(sum(ONU[count]), FILTER(DateTable,DateTable[Date] = eomonth(DateTable[Date],-1)))

What I try to do is ge the sum of last day of last month next to the value of current month

So 

date                sum                                   sum(eomonth -1)                                               Diff

2022-01-31   <sum(ONU[count])>          <sum(ONU[count])> (2021-12-31)                   <col2> - < col1>