SQL Interview/Exam Questions With Details Explanation : 2025

Practice for SQL Certification with 320+ Questions Covering SQL Queries, Administration, and Performance!

Preview this Course

GET COUPON CODE

Description

SQL Interview Questions – 320+ Comprehensive Practice Questions

Are you preparing for an SQL interview? This extensive collection of 320+ SQL interview questions will help you enhance your database skills, gain confidence, and get ready to tackle real-world SQL challenges. Whether you're a beginner or an experienced professional, these questions cover essential SQL concepts with clear, detailed explanations.

What Topics Will We Cover in This Practice Test?

Basic SQL Queries

What are the different types of SQL statements?

How do you retrieve unique values from a table?

What is the difference between WHERE and HAVING?

Explain the difference between COUNT(*), COUNT(column), and COUNT(DISTINCT column).

Joins and Relationships

Explain different types of joins (INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN, CROSS JOIN).

How do you perform a self-join?

What is the difference between JOIN and UNION?

Subqueries and Common Table Expressions (CTEs)

What is a subquery? Provide an example.

What is the difference between a correlated and non-correlated subquery?

When should you use CTEs instead of subqueries?

Aggregation and Grouping

How does GROUP BY work? Give an example.

What is the difference between GROUP BY and PARTITION BY?

How do you find the second highest salary in an employee table?

Indexes and Performance Optimization

What are indexes? How do they improve performance?

What is the difference between a clustered and non-clustered index?

What are some ways to optimize a slow query?

Constraints and Data Integrity

What are primary and foreign keys?

What is the difference between UNIQUE and PRIMARY KEY?

How do CHECK and DEFAULT constraints work?

Transactions and Concurrency Control

What are transactions, and what are ACID properties?

What is the difference between COMMIT, ROLLBACK, and SAVEPOINT?

Explain isolation levels and their effect on transactions (READ COMMITTED, READ UNCOMMITTED, REPEATABLE READ, SERIALIZABLE).

Stored Procedures, Functions, and Triggers

What is the difference between a stored procedure and a function?

How do you pass parameters to a stored procedure?

What is a trigger? Give an example of when to use one.

Normalization and Database Design

What are normalization and denormalization?

Explain the different normal forms (1NF, 2NF, 3NF, BCNF).

What is the difference between OLTP and OLAP databases?

Advanced SQL Concepts

What is a window function? Provide an example.

Explain the use of RANK(), DENSE_RANK(), and ROW_NUMBER().

How do recursive queries work in SQL?

NoSQL vs SQL

What are the main differences between SQL and NoSQL databases?

When should you choose NoSQL over SQL?

Real-World Problem-Solving Scenarios

How would you design a database for a library management system?

How do you handle duplicate records in SQL?

How do you write an efficient query to find employees with the highest salary in each department?

Why Choose This SQL Interview Question Bank?

320+ Curated Interview Questions – Designed to test your knowledge across key SQL concepts, from basic queries to advanced optimization techniques.

Detailed Explanations – Every question includes in-depth explanations to ensure you understand the logic behind SQL queries.

Real-World Scenarios – Approximately 40-45% of the questions focus on practical applications, helping you prepare for real job challenges.

Up-to-Date Content – Covers the latest SQL techniques and best practices to ensure you're interview-ready.

Get Ready to Ace Your SQL Interview!

With a well-structured question set, expert explanations, and real-world problem-solving exercises, you'll be well-prepared to impress hiring managers and land your next SQL-related role.

Start practicing today and take your SQL expertise to the next level!

Who this course is for:

• Individuals looking for a job can use practice tests to improve their SQL skills and knowledge, helping them stand out in the job market with SQL Certification.
• Those who feel unsure about their abilities can use practice tests to build confidence by getting familiar with the exam format and preparing well for SQL Certification.
• Anyone who wants to improve their test-taking skills can benefit from practice tests, helping them try different strategies and get better at managing time for SQL Certification.
• Data analysts who want to validate their SQL knowledge can use practice tests to refine their query skills and prepare for SQL Certification.
• IT professionals looking to transition into database management can take practice tests to strengthen their SQL expertise for SQL Certification.
• Professionals aiming for promotions in data-driven roles can use SQL Certification practice tests to validate their SQL skills and improve career prospects.
• Anyone looking to transition into a data-related role can use SQL Certification practice tests to develop essential database querying skills.