Ongoing Comparison of Last Completed Month to Prior Month

[Anonymous]

Based on my table below I want to isolate that 13 figure as a measure and be able to plot it on a graph so that I can compare what makes up that 13 difference (which clients gained the most revenue last month compared to the month prior)

I tried to do a conditional column that would look only at April but when I did that and applied the filter it caused the last month figure to be blank so the difference was 73.  When may data is loaded I want to compare may with april and so on.

flag = IF('Date'[Year]=[Today-year] && 'Date'[Monthnumber]=[lastmonth],1,0) -- didn't work 

Last Month Revenue = CALCULATE([Revenue], DATEADD('Date'[Date].[Date], -1, MONTH))

Difference = Revenue - Last Month Revenue 

Date	This Month Revenue	Last Month Revenue	Difference
February 20	50	38	12
March 20	60	50	10
April 20	73	60	13
May 20	No data yet, so blank	73	-73

[Greg_Deckler · Accepted solution]

It's difficult to say definitively given the information provided. Please see this post regarding How to Get Your Question Answered Quickly: https://community.powerbi.com/t5/Community-Blog/How-to-Get-Your-Question-Answered-Quickly/ba-p/38490

The most important parts are:
1. Sample data as text, use the table tool in the editing bar
2. Expected output from sample data
3. Explanation in words of how to get from 1. to 2.

That said, from what you describe, you generally do things like that the following way:

Diff =
  VAR __ThisMonthRevenue = SUM([Revenue]) //should have current month in context
  VAR __CurrentDate = MAX([Date]) //again, current month in context have a date in current month
  VAR __LastMonthDate = EOMONTH(__CurrentDate,-1) // end date of last month
  VAR __LastMonthStart = DATE(YEAR(__LastMonthDate),MONTH(__LastMonthDate),1)) //1st of last month
  VAR __ThisMonthStart = DATE(YEAR(__CurrentDate),MONTH(__CurrentDate),1)) //1st of current month
RETURN
  __ThisMonthRevenue - SUMX(FILTER(ALL('Table'),[Date]>=__LastMonthStart && [Date]<__ThisMonthStart),[Revenue]) //ALL overrides filter context

This is a general solution that would need to be adapted to your data.