Context

At companies like FleetOps, operational dashboards often need both row-level filtering and group-level filtering. Interviewers ask this to confirm that you understand when filtering happens in SQL execution.

Core question

Explain the difference between WHERE and HAVING in SQL. In your answer, cover:

1. What each clause filters
2. When each clause is evaluated in a query
3. Why WHERE cannot usually filter aggregate results directly
4. A simple example showing both clauses used correctly in the same query

Scope guidance

Keep the explanation practical. The interviewer is usually looking for a clear distinction between row-level filtering and post-aggregation filtering, plus one or two examples of common mistakes such as using HAVING when WHERE is more appropriate.