Join it

A clean table is only useful once you can connect it to the rest of the estate. rides alone can't tell you which city earned the most, or whether a driver got paid what the records say — you need cities, riders, driver_payouts, driver_documents. The danger at this size isn't writing a join that fails, it's writing one that runs fine and returns the wrong number: join two tables that both have several rows per parent, and a SUM silently multiplies before it ever adds. Every step below is graded.