Perform an average per month and class

Hi, DanCasSan 

Based on your description, I created data to reproduce your scenario.

Table:

Calendar:

Calendar = CALENDARAUTO()

There is a one-to-many relationship between two tables. I create a 'Month-Year' column in 'Calendar' table.

Month-Year = 
IF(
    MONTH('Calendar'[Date])<10,
    YEAR('Calendar'[Date])&"0"&MONTH('Calendar'[Date]),
    YEAR('Calendar'[Date])&MONTH('Calendar'[Date])

)

You may create a measure as follows.

Average = 
IF(
    ISFILTERED('Calendar'[Month-Year]),
    BLANK(),
    DIVIDE(
        CALCULATE(
            SUM('Table'[Value]),
            ALL('Calendar'[Month-Year])
        ),
        CALCULATE(
            DISTINCTCOUNT('Calendar'[Month-Year]),
            ALLSELECTED('Calendar')
        )    
    )
)

Result:

If I misunderstand your thoughts, please show us your expected result and sample data. Do mask sensitive data before uploading. Thanks

Best Regards

Allan

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