Your question is Combine Multi-Source Operational Data. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
At companies like FleetOps, operational records often come from multiple systems such as warehouse apps, delivery tools, and support platforms. Analysts need a consistent way to combine these datasets before reporting or downstream processing.
Explain how you would use UNION and UNION ALL to combine operational data from multiple sources. In your answer, cover:
UNION and UNION ALLThe interviewer expects a practical explanation, not just syntax. You should describe how to standardize source datasets, choose the right set operator, and prepare the combined result for reporting or aggregation in PostgreSQL.