Context

Financial analysts at Relias often need to summarize large operational datasets into a format that makes trends easy to compare across time, region, or product line. Pivot tables are a common way to turn detailed rows into a compact reporting view.

Question

Explain how you would use pivot tables to analyze a large dataset from a Relias financial reporting workflow. In your answer, cover:

1. What a pivot table does and why it is useful for financial analysis
2. Which row fields, column fields, filters, and value aggregations you would choose
3. How you would use SQL to produce the same result in PostgreSQL when a BI tool or spreadsheet pivot is not enough
4. What limitations or risks to watch for when working with large datasets

Scope guidance

Keep the answer practical and analyst-focused. The interviewer is looking for a clear explanation of how pivot-style analysis helps summarize large datasets, how to structure the dimensions and measures, and how SQL aggregations can replicate or extend a pivot table in PostgreSQL.