Context

Financial reporting queries must be correct, repeatable, and easy to validate. Small SQL mistakes in filters, grouping, or null handling can produce materially wrong totals.

Core question

Explain how you ensure financial reports are accurate and consistent when writing SQL. In your answer, discuss:

1. How you validate source data before reporting
2. How you prevent aggregation errors and inconsistent business logic
3. How you reconcile report outputs against known control totals
4. How you handle nulls, duplicates, refunds, and late-arriving records

Scope guidance

The interviewer is looking for a practical SQL-focused explanation, not accounting theory. Cover the checks, query design habits, and validation steps you would use to make sure the same report produces reliable results over time.