Need help constructing a basic 3, 6, and 12 month moving average

[socalkid]

Hello all,

I have a question re: how to calculcate a moving 3 month, 6 month and 12 month average for some headcount data. My main data table looks like this: 

So I have the count by date, department, work category and location. My goal is to be able to set up a table where I can see the 3-month, 6-month, and 12-month averages for each location, department, work category and then sum up this average if I need to. For example, I'd like to be able to see the overall 3-month average for all of Operations in Shanghai for August 2020. Is this possible? I've been reading about setting up a date table but I'm not sure if that's required for this. Thank you in advance.

[amitchandak]

@socalkid , Try like

3 Month Avg = CALCULATE(AverageX(Values('department'[department]),calculate(Sum('Table'[Value)))
,DATESINPERIOD('Date'[Date ],MAX('Date'[Date ]),-3,MONTH))

6 Month Avg = CALCULATE(AverageX(Values('department'[department]),calculate(Sum('Table'[Value)))
,DATESINPERIOD('Date'[Date ],MAX('Date'[Date ]),-6,MONTH))

6 Month Avg = CALCULATE(AverageX(Values('Date'[MONTH Year]),calculate(Sum('Table'[Value)))
,DATESINPERIOD('Date'[Date ],MAX('Date'[Date ]),-6,MONTH))

3 Month Avg = CALCULATE(AverageX(Values('Date'[MONTH Year]),calculate(Sum('Table'[Value)))
,DATESINPERIOD('Date'[Date ],MAX('Date'[Date ]),-3,MONTH))

Rolling Months Formula: https://youtu.be/GS5O4G81fww

Average of Rolling, Average of Snapshots: https://youtu.be/_pZRdLAJxxA

Power BI Window function Rolling, Cumulative/Running Total, WTD, MTD, QTD, YTD, FYTD: https://youtu.be/nxc_IWl-tTc