Issue with Missing data in Calculation

Hi,MNedix, sanalytics and Kedar_Pande .

thanks for your concern about this issue.

Your answer is excellent!
And I would like to share some additional solutions below.
Hello,ginalu .I am glad to help you.

Here is my test.

I noticed that you have a one-to-many relationship between your two tables, try using the RELATED function in the filter function on a field in the other table

like this.

Calculate the number of users who have been active in the last seven days.

Recent7DaysActiveUsers = 
CALCULATE(
    DISTINCTCOUNT(USERUNQ[user_id]),
    FILTER(
        LESSONN,
        TRUNC(LESSONN[start_time]) >= TODAY() - 7 &&
        TRUNC(LESSONN[start_time]) < TODAY() &&
        RELATED(USERUNQ[user_id]) = LESSONN[teacher_id]
    )
)

Below is my test data:

I hope my suggestions give you good ideas, if you have any more questions, please clarify in a follow-up reply.
Best Regards,
Carson Jian,
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