Filter Date from multiple tables

Hello!

First, start by creating a one-to-many relationship from Table2 to Table1.

Then I created two measures to solve this, one for calls and one for emails:

Calls Before First Purchase Date = CALCULATE(SUM(Table1[Calls]), FILTER(Table1, Table1[Date] <= RELATED(Table2[First Purchase Date])))

Emails Before First Purchase Date = CALCULATE(SUM(Table1[Emails]), FILTER(Table1, Table1[Date] <= RELATED(Table2[First Purchase Date])))

Calculate the sum of the number of calls/emails for each Customer ID, but apply a filter such that the date of the emails are earlier than the first purchase date. Since we have created the one-to-many relationship between these two tables, the related function can find the corresponding first purchase date for the given Customer ID.

Hope this helps!