Top SQL MCQ Questions to Boost Your Knowledge and Skills
Estimated study time: 166 minutes. Test your SQL fundamentals with these practice questions.
Multiple-choice questions are one of the fastest ways to check whether you actually understand SQL concepts, not just recognize the syntax. Here's a curated set of SQL MCQs covering the topics that show up most often in exams and interviews.
Sample Question 1
Which keyword is used to remove duplicate rows from a result set?
- A) UNIQUE
- B) DISTINCT
- C) FILTER
- D) REMOVE
Answer: B — DISTINCT. It removes duplicate rows from the output of a SELECT statement.
Sample Question 2
Which type of JOIN returns all rows from the left table, and matching rows from the right?
- A) INNER JOIN
- B) RIGHT JOIN
- C) LEFT JOIN
- D) CROSS JOIN
Answer: C — LEFT JOIN. Unmatched rows from the right table appear as NULL.
Sample Question 3
Which normal form eliminates transitive dependency?
- A) 1NF
- B) 2NF
- C) 3NF
- D) BCNF
Answer: C — Third Normal Form (3NF) removes columns that depend on non-key attributes.
Topics These Questions Usually Cover
- Joins, keys, and constraints
- Normalization and database design
- Aggregate and window functions
- Indexing and query performance basics
Working through MCQs regularly builds the kind of quick recall you need during timed exams and technical interview rounds alike.