How to use filters in the measures

[at01]

Hello,

I am discovering DAX and I would need some help understanding what I do wrong in building my measures.

I have the following measure:

-------------------------------------------------------------------------------------

Contacted Clients =

var startDate=min('Date'[Date])

var endDate=max('Date'[Date])

var countClients=distinctcount(Communication[Client ID])

Return

calculate( countClients,

filter(Communication, Communication[Message Created At] >= startDate && Communication[Message Created At] <=endDate)

)

-------------------------------------------------------------------------------------

which counts the number of clients that have been contacted during the period between the dates that are choosen by the user (based on the Date[Date] column.

I want to also calculate the number of clients that have been contacted 30 days prior to the first date choosen by the user. SO I defined the following measure:

-------------------------------------------------------------------------------------

Contacted Clients 30 days prior=

var startDate=min('Date'[Date])-30

var endDate=min('Date'[Date])

var countClients=distinctcount(Communication[Client ID])

Return

calculate( countClients,

filter(Communication, Communication[Message Created At] >= startDate && Communication[Message Created At] <=endDate)

)

-------------------------------------------------------------------------------------

but I get the same number in Contacted Clients and Contacted Clients 30 days Prior

I suppose I do not understand exactly how it should work, any tips on what needs correcting? Is there an issue that the Date and Communication tables are linked using a Many to one relationship table between Communication[Message Created At] and Date[Date] column?

I have tried ALL(Communication) as well to make sure to ignore the filters but I suppose it is not the issue.

Thank you very much for any tips on how to correct this!

[AlB]

Hi @at01 

VAriables in DAX are immutable. Their value won't change after declaration. So that calculate will not have any effect whatsoever. Try this: 

Contacted Clients =
VAR startDate =
    MIN ( 'Date'[Date] )
VAR endDate =
    MAX ( 'Date'[Date] )
RETURN
    CALCULATE (
        DISTINCTCOUNT ( Communication[Client ID] ),
        FILTER (
            Communication,
            Communication[Message Created At] >= startDate
                && Communication[Message Created At] <= endDate
        )
    )

Please accept the solution when done and consider giving a thumbs up if posts are helpful.  Contact me privately for support with any larger-scale BI needs, tutoring, etc.