Senior questions test whether your solution remains correct when the data changes. A query can return plausible numbers while multiplying order headers, dropping empty arrays or selecting an arbitrary profile update. Explain the failure mode you are preventing, then write the SQL that enforces the requested rule.
Several tasks combine previously practiced constructs. Keep the source grain visible in a CTE when it makes the logic easier to review. The scenario questions distinguish a supported decision from a claim that the available evidence can't establish. You can calculate an observed rate or estimate compute credits without claiming a causal reason or a complete invoice amount. These are original practice scenarios; no certification or employer supplied the questions.