SQL vs Excel for Large Datasets

Context

Analysts often start in Excel, but large datasets quickly expose limits in performance, repeatability, and data quality control. Interviewers ask this question to understand whether you can translate spreadsheet-style analysis into scalable SQL workflows.

Core Question

Explain how you would analyze large datasets efficiently when a task is commonly done in Excel, but the data lives in a database. Discuss:

1. Why Excel becomes inefficient at scale
2. Which SQL techniques replace common Excel operations like filtering, lookups, pivots, and summaries
3. How SQL improves performance, reproducibility, and data accuracy
4. When Excel is still useful after SQL processing

Scope Guidance

Keep your answer practical. The interviewer is not looking for a critique of Excel alone; they want to hear how you would use SQL to do the heavy data manipulation, reduce dataset size, aggregate results, and then optionally export a smaller result set for final review or presentation.