Power BI Desktop: Variables in Measures

Hi fturmo,

The result of that formula is OK for each individual member but i don't know how to calculate the aggregate (average) for all the rows in the table.

In this scenario, you may need two measures to work this out. First measure to calculate the time difference for the individual column which is similar to the measure you provided above.. The formula below is for your reference.

Measure Time For Individual Member =
VAR startdate =
    MAX ( Table1[Start Date] )
VAR enddate =
    MAX ( Table1[End Date] )
VAR Firstdayend =
    DATE ( YEAR ( startdate ), MONTH ( startdate ), DAY ( startdate ) + 1 )
VAR LastdayStart =
    DATE ( YEAR ( enddate ), MONTH ( enddate ), DAY ( enddate ) )
VAR LastdayEnd =
    DATE ( YEAR ( enddate ), MONTH ( enddate ), DAY ( enddate ) + 1 )
VAR secondsfirstday =
    IF ( Firstdayend <= startdate, 0, DATEDIFF ( startdate, Firstdayend, SECOND ) )
VAR secondslastday =
    IF (
        enddate >= LastdayStart
            && enddate <= LastdayEnd,
        DATEDIFF ( LastdayStart, enddate, SECOND ),
        IF ( enddate > LastdayEnd, DATEDIFF ( LastdayStart, LastdayEnd, SECOND ), 0 )
    )
VAR secondsmidday =
    (
        CALCULATE (
            DISTINCTCOUNT ( 'Calendar'[Date Calculations] ),
            FILTER (
                'Calendar',
                'Calendar'[Date Calculations] > startdate
                    && 'Calendar'[Date Calculations] < enddate
                    && 'Calendar'[Is Weekday] = TRUE ()
            )
        )
            - 1
    )
        * 3600
        * 24
RETURN
    ( secondsfirstday + secondslastday
        + secondsmidday )
        / 3600

Then use a new measure to sum each individual time difference together for the table.

Measure Avg Time = SUMX ( Table1, [Measure Time For Individual Member] )

Regards