Distinctcount relatedtable date_Key to month

[power_roboter]

Hi experts,

I have a table with tracking data [userId, date_Key,..] and a related date table [date_Key, month, year etc.]. The tables are linked via the date_Key. Now I want to calculate the active months of a user.

I think calculate(DISTINCTCOUNT(RELATEDTABLE(Date)) does not work, because calculate only refers to one line of a user. The result for this is always 1.

Can you help me?

EVALUATE

DISTINCT (

SELECTCOLUMNS (
FILTER (
'∑ Tracking Data',
'∑ Tracking Data'[Application] = "product_a"
),
"userID", '∑ Tracking Data'[userId],
"numberOfActiveMonths", calculate(DISTINCTCOUNT(RELATEDTABLE(Datum)),
 "numberOfUsageDays", calculate(DISTINCTCOUNT('∑ Tracking Data'[Datum_Key]),ALLEXCEPT('∑ Tracking Data','∑ Tracking Data'[userId]),'∑ Tracking Data'[Datum_Key] >= 20200101)
))

[amitchandak]

@power_roboter , not clear on what is an active user.

Is it very similar to

new vs repeat customer
https://community.powerbi.com/t5/Desktop/Churn-Rate-lost-Customer/m-p/1173754#M529196
https://blog.enterprisedna.co/new-vs-existing-customers-advanced-analytics-w-dax/
https://www.sqlbi.com/articles/computing-new-customers-in-dax/

[power_roboter]

An active user is a user, that has an entry in the tracking table. If the user has an entry for 20200101 he is an active user in january 2020.