Juniper Returns is reviewing credits from a depot extract. The practice table uses return_id, account_id, credit, return_status, depot and received_at. Unknown credits remain unknown, and negative credits remain visible for investigation. You need both detailed exceptions and totals at the requested grain.
Reuse the operations and data skills from the course. Query tasks run against a fresh returns extract; each task starts from its stated setup, so you can solve them independently. Keep NULL handling explicit and do not use a distinct result to hide a faulty relationship. The final decisions concern access, replay and recovery. Those decisions are checked as choices because the training workspace does not run real distributed clusters or administer an external production account. Explain the consequence of each decision to yourself before checking it.