Context

Finance and operations teams often use Excel pivot tables to summarize transactions and compare expected versus actual totals during reconciliations. In SQL roles, interviewers want to know how you would translate that same thinking into database queries.

Question

Explain how advanced Excel features such as pivot tables and variance analysis support reconciliations, and how you would reproduce the same workflow in PostgreSQL. In your answer, discuss:

1. How pivot-style summaries help identify mismatches quickly
2. How variance analysis is used to compare two sets of amounts or counts
3. Which SQL techniques you would use instead of Excel features
4. How you would investigate exceptions after finding a variance

Scope guidance

Keep the answer practical and interview-focused. You do not need to discuss spreadsheet mechanics in detail; focus on the reconciliation logic, the SQL equivalents, and how summary-level checks lead into row-level investigation.