When building Power BI reports we often need to join two (or more) tables together, but what if the relationship is defined by two or more columns? Relationships in Power BI are limited to single columns, but whilst this seems like a major limitation there is actually a simple solution to create a relationship with multiple columns in Power BI.
To create a relationship with multiple columns in Power BI we simply need to create a new column by merging the required columns together. What’s more, if we use the same name in both queries Power BI will automatically create the relationship for us.