SQL Interview Questions
Hey there! This article has everything you need to prepare for SQL interview questions. Our article presents the top database interview questions and the smartest candidate questions for strategic assessment.
The article presents a compilation of SQL interview questions, unique questions for employers, supervisor interview questions, situational questions, and web programming interview questions for guidance.
We derive the information directly from essential facts, eliminating any unnecessary details.
Let’s dive in!
Also check: SQL Database Cheat Sheets
Beginner Level SQL Interview Questions
1. What is SQL?
SQL is a language to manage and query data in a database.
2. What does SQL stand for?
It stands for Structured Query Language.
3. What is a primary key?
A primary key is a column that uniquely identifies each row in a table.
4. What is a foreign key?
A foreign key links one table’s column to a primary key in another table.
5. What is the difference between DDL and DML?
DDL changes the database structure (like CREATE TABLE). DML changes data (like INSERT).
6. What does SELECT do?
SELECT retrieves data from a database table.
7. How do you filter results in SQL?
By using the WHERE clause with conditions.
8. What is a JOIN?
JOIN combines rows from two tables based on a related column.
9. Name the main types of JOIN.
INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN.
10. What is GROUP BY used for?
It groups rows that share a value so you can use aggregate functions.
11. What is HAVING used for?
HAVING filters groups after using GROUP BY.
12. What is a subquery?
A subquery is a query inside another query.
13. What is an INDEX?
An index speeds up data retrieval on a column.
14. What is normalization?
Normalization organizes tables to reduce data duplication.
15. What is ACID in databases?
ACID stands for Atomicity, Consistency, Isolation, Durability for transactions.
16. What is a view?
A view is a virtual table based on a query.
17. What is a stored procedure?
A stored procedure is a saved set of SQL statements you can call.
18. What is a transaction?
A transaction is a group of SQL statements that run together.
19. What is the difference between DELETE and TRUNCATE?
DELETE removes rows one by one and can be rolled back. In some systems, TRUNCATE swiftly removes all rows and does not allow for rollbacks.
20. What is SQL injection?
It’s a security flaw where attackers add malicious SQL to a query.
Check: SQL roadmap
Final Thoughts
That’s it! The provided SQL interview questions will ensure readiness for your upcoming interview session. Identify and choose the interview questions that best match your work position, then practice them by speaking out loud.
The compiled list of questions serves two purposes: first, for studying, and second, for generating questions for candidate interviews. Maintain honesty while you proceed with your luck! ✅
Good luck! You’ve got this.
