Sql quiz

Test your Sql knowledge with a free interactive quiz — 50 questions with answers and explanations. No signup needed to play.

What does SQL stand for, and what is it primarily used for?

1. What does SQL stand for, and what is it primarily used for?
2. ``` SELECT u.name, o.id FROM users u JOIN orders o ON o.user_id = u.id; ``` Which type of join is this (implicit / explicit)?
3. What does `SELECT DISTINCT col FROM t` return?
4. What does a `UNIQUE` constraint provide that `PRIMARY KEY` does not (and vice versa)?
5. Which clause filters rows in a query?
6. Which clause filters AGGREGATED groups, not individual rows?
7. Which keyword sorts the result set?
8. What is the purpose of a column alias (`SELECT total AS amount`)?
9. What does `WHERE country IN ('UA', 'PL', 'DE')` do?
10. What is the practical danger of running `UPDATE users SET active = false;` without a `WHERE` clause?
11. What does `INSERT INTO users (email) VALUES ('a@b')` do?
12. What does a `FOREIGN KEY` constraint do?

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