What is the difference between LEFT JOIN and RIGHT JOIN?

Short answer: LEFT JOIN: Returns all records from the left table, and matched records from the right table. If there's no match, NULL values are returned for the right table's columns. RIGHT JOIN: Returns all records from the right table, and matched records from the left table. If there's no match, NULL values are returned for the left table's columns.

Real-world example (ShopNest)

An invoice query INNER JOINs Orders and OrderItems, and LEFT JOINs Discounts so orders without a coupon still appear.

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.