Reza Rad shows how to build a Cartesian product using Power Query:
Sometimes, you need to create a multiplication of all sets of all pairs from two different data tables in Power BI. This action is different from Merge (Join) because there is no matching key columns and no way to relate the two tables together. However, you want to create a multiplication as a flatten table. If this process is needed to be done in Power Query, then there is a simple trick to do it, In this article, I’ll explain how you can do it.
Read on for that trick.