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SanderVeeken's avatar
SanderVeeken
Icon for Helper III rankHelper III
3 years ago
Solved

DAX using earliest/max date over two tables

Hello everyone,   I have a datamodel of courses with subscribers, each in their own table. They're linked by the unique course ID. The subscriptions have dates, and the courses have starting dates....
  • johnt75's avatar
    johnt75
    3 years ago

    Try

    Average days before course starts =
AVERAGEX (
    'Courses',
    VAR FirstSubscriptions =
        TOPN (
            'Courses'[Min subscribers],
            RELATEDTABLE ( 'Subscriptions' ),
            'Subscriptions'[Subscription date], ASC
        )
    VAR LatestSubscription =
        MAXX ( FirstSubscriptions, 'Subscription date' )
    RETURN
        'Courses'[Start date] - LatestSubscription
)
Greg_Deckler's avatar
Greg_Deckler
Icon for Community Champion rankCommunity Champion
3 years ago

SanderVeeken Sorry, having trouble following, can you post sample data as text and expected output?
Not really enough information to go on, please first check if your issue is a common issue listed here: https://community.powerbi.com/t5/Community-Blog/Before-You-Post-Read-This/ba-p/1116882

Also, please see this post regarding How to Get Your Question Answered Quickly: https://community.powerbi.com/t5/Community-Blog/How-to-Get-Your-Question-Answered-Quickly/ba-p/38490

The most important parts are:
1. Sample data as text, use the table tool in the editing bar
2. Expected output from sample data
3. Explanation in words of how to get from 1. to 2.