What is a CASE statement in SQL?

Short answer: The CASE statement provides conditional logic in SQL queries. It returns a value based on certain conditions.

Example code

SELECT name, CASE WHEN salary > 70000 THEN 'High' WHEN salary BETWEEN 40000 AND 70000 THEN 'Medium' ELSE 'Low' END AS salary_range FROM employees;

Real-world example (ShopNest)

ShopNest’s SQL Server database stores customers, products, and orders. Good indexes and clear foreign keys keep checkout queries fast and safe.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.