Many to many relationship in BI

Question

I've just started to use Power BI designer and noticed a documentation that mentions being able to establish a many-to-many relationship within the tool. But when I try to do the many-to-many join, I receive an error that says "You can't create a relationship between these two columns because one of the columns must have unique values."

Can anyone tell me what am I doing wrong?

Thanks in advance.

Answer 1

This is an error in the documentation. 

As you've noted, you can't specify this in the relationship dialog. Many to many relationships require a junction table to work (a table in the middle that says how the two tables should be correlated.) You may be able to get what you want with a 1:1 or M:1 relationship.