SELF-CHECK
A customer has 2 sales rows and 3 ticket rows. What can a direct join create?

REFERENCE REASONING
It can create 6 rows and multiply measures. Aggregate each fact at the intended grain or use a model that prevents fan-out before comparing measures.

This is a reasoning reference for the supplied fictional case, not an executed app or tested cloud deployment. Alternative approaches are valid when supported by stated assumptions and evidence.
