Calculate a measure that checks if data is blank and If so use previous month avg to do calcuations

[salim123]

Hello every one,

I am posting this for the second time, since I had no help in the first time, any remark would be helpful.

So I am new to dax and I am writing this measure that calculates a weighted value (SUMPROD(volume, TS) divided bySUM(Volume)), but the problem is that TS values are not there every day, so I have to multiply the volume with TS avg of the previuos month, I see that my reasoning is right bu something dosen't seem to work.
Here is My measure :

TS Ponderee (Madcap) =

        DIVIDE(

            SUMX('all years data',

            var c=0

            return

                 if('all years data'[T/S]<>BLANK(),'all years data'[Vol L]*'all years data'[T/S], 'all years data'[Vol L]*[previous_month_ts])

            ),

            SUMX(

                'all years data', 'all years data'[Vol L]

            )

        )

The previous month measure:

previous_month_ts = Calculate(

                        [T/S avg],

                        DATEADD(DateAnalyse[Date],-30,DAY)

                    )

Here is a piece of my data , as you can T/S is not there every time:

And here what I get when I show data as a table:

Any remark would be helpful.
thank you

[tamerj1]

Hi @salim123 
Please try

TS Ponderee (Madcap) =
VAR PreviousMonthTS = [previous_month_ts]
VAR Numerator =
    SUMX (
        'all years data',
        IF (
            'all years data'[T/S] <> BLANK (),
            'all years data'[Vol L] * 'all years data'[T/S],
            'all years data'[Vol L] * PreviousMonthTS
        )
    )
VAR Denominator =
    SUMX ( 'all years data', 'all years data'[Vol L] )
RETURN
    DIVIDE ( Numerator, Denominator )

[salim123]

Thank you for your feedback.

I tried the formula provided in your response, but it is still the same problem:

[tamerj1]

@salim123 
Previous TS is measure right?

[salim123]

Yes and here is its formula:

previous_month_ts = Calculate(

                        AVERAGE([T/S]),

                        DATEADD(DateAnalyse[Date],-30,DAY)

                    )

[tamerj1]

@salim123 
Please test the following 

TS Ponderee (Madcap) =
SUMX ( 'all years data', IF ( 'all years data'[T/S] <> BLANK (), 1, 0 ) )

[salim123]

Here is what it outputs:

[tamerj1]

@salim123 

In the first measure I shared

RETURN 

    Denominator

[salim123 · Accepted solution]

Thank you for all your feedbacks.

Finally I  found the solution, what I did is that I added a calculated column where I store the multiplication of Volume and T/S:

And then I used it with the formula as follows:

TS Ponderee (Madcap) =

VAR PreviousMonthTS = [previous_month_ts]

VAR Numerator =

    SUMX (

        'all years data',

        IF (

            'all years data'[T/S] <> BLANK (),

            'all years data'[volume*T\S],

            'all years data'[Vol L] * PreviousMonthTS

        )

    )

VAR Denominator =

    SUMX ( 'all years data', 'all years data'[Vol L] )

RETURN

    DIVIDE ( Numerator, Denominator )

Thank alot for your efforts.