Top 100+ SQL Interview Questions and Practice Exercises

Are you gearing up for a SQL interview? This article is packed with over 100 SQL interview questions and practical exercises, organized by topic, to help you prepare thoroughly and approach your interview with confidence.

SQL is essential for many jobs, like data analysis, data science, software engineering, data engineering, testing, and many others. Preparing well for a SQL interview is crucial, no matter what role you're aiming for.

Searching for a new job can be really stressful, whether you're choosing to switch, have been laid off, or are looking for your first job. That's why being well-prepared is essential.

In this article, I've gathered over 100 SQL interview questions and exercises. These questions are spread across various articles published at LearnSQL.com. I have organized the articles by topic. Feel free to explore only the topics related to your specific job. I've also included tips to help you prepare for your interview.

SQL Interview Preparation Tips

Review Your SQL Knowledge

Start preparing for your SQL interview well in advance. Once you're invited to an interview (Congratulations!), ask your recruiter what to expect and what is the format of the interview. For the SQL part you can usually expect coding exercises on an automated testing platform, a take-home assignment, or a whiteboard session.

Practice Regularly

The key to performing well in a SQL interview is practice. You'll likely be nervous, so the more familiar you are with SQL, the more instinctive your responses will become. Practice a variety of SQL problems so that querying becomes second nature to you.

Familiarize Yourself with the Testing Platform

If your interview involves using a specific coding platform, try to get comfortable with it beforehand. Many platforms offer a demo or practice session, so take advantage of this feature to familiarize yourself with the interface. This familiarity can help reduce stress and improve your performance during the actual interview.

Prepare for Different Types of Questions

• Coding Platform Questions: Whether during the interview or as a take-home task, make sure you understand the typical questions and problems that might appear on these platforms. Practice solving similar problems under timed conditions.
• Whiteboard Interviews: Be ready to write code in pseudocode and discuss your thought process. Focus on explaining the concepts and logic behind your solutions more than the exact syntax, which demonstrates a deeper understanding of the problem-solving process.

Additional Tips

• Review Key SQL Concepts: Make sure you're comfortable with all fundamental SQL operations such as joins, subqueries, window functions, and aggregation. Also, review more advanced topics if the job role demands it.
• Mock Interviews: Consider doing mock interviews with friends or mentors to simulate the interview environment. This practice can help you manage time and stress effectively.
• Rest Well: Ensure you're well-rested before the interview day; a clear mind will help you think and perform better.

By incorporating these strategies into your preparation, you can approach your SQL interview with confidence and increase your chances of success.

Review Your SQL Knowledge

Begin by refreshing your SQL knowledge, particularly if you haven't used it in a while. In this section we have collected some resources to assist you.

Our "SQL Basics" course is perfect for beginners or anyone needing a brief review. It covers both basic and intermediate SQL topics. In this course, you will actively write SQL code in various exercises, which will help you grow more confident in your SQL skills as you advance.

Explore 55+ General SQL Interview Questions

After you have refreshed the basics, check out these articles filled with SQL interview questions to help you prepare:

• Complete SQL Practice for Interviews — includes 16 SQL interview questions with practical exercises.
• 16 SQL Interview Questions for Business Analysts — SQL interview questions tailored for analysts.
• 8 Common Entry Level SQL Developer Interview Questions — great for beginners.
• Top 15 SQL Interview Questions in 2021 — a compilation of recent and relevant questions.

Practice, Practice, Practice, …

After refreshing your SQL skills, it’s important to keep practicing. Interviews can be stressful, and even straightforward topics can become challenging under pressure. The more you practice, the more confidently you can handle questions and problem-solving during an interview.

Here are some practice resources we recommend:

• SQL Practice track – This series includes 10 comprehensive SQL practice courses to sharpen your skills, perfect for those looking for hands-on practice. Key courses in this track include:
• SQL Practice Set – Provides a range of exercises across various SQL topics and databases.
• SQL Practice: A Store – Specifically designed for data analysts, this course offers practical SQL tasks using a database from an online store.
• SQL Practice: Blog & Traffic Data – Perfect for marketers and data analysts, this course focuses on analyzing traffic data from a pet store blog.
• SQL Practice Databases – Gathers a variety of datasets for you to practice with. With no guided exercises, you are encouraged to explore the data, formulate your own questions, and find the answers yourself.

You can find many SQL practice materials and premium resources in Your Guide to SQL Practice at LearnSQL.com.

SQL Cheat Sheet

Lastly, we recommend our SQL Basics Cheat Sheet. It is a quick reference guide that covers basic SQL syntax. Keep it handy as you review your SQL knowledge and practice your skills.



Explore 50+ Specific SQL Topic Interview Questions

After you have refreshed your basic SQL knowledge, you might notice certain topics that are trickier for you or more relevant to your specific job role. In this section we've compiled resources that help you prepare for interview questions on specific SQL topics.

JOINs

JOINs are a fundamental SQL construction used to combine data from multiple tables. They are also an essential topic at any SQL interview.

In our article The Top 10 SQL JOIN Interview Questions with Answers we've gathered the 10 most common questions about SQL JOINs that you might encounter in interviews. For each question we give you a detailed answer that will highlight what the interviewer is looking for in each question.

If you want to practice SQL JOINs, we recommend our interactive SQL JOINs course. It focuses on exercises specifically about SQL JOINs and contains 93 practice exercises to help you get confidence in your joining skills.

Additionally, we recommend Your Complete Guide to SQL JOINs, a comprehensive article that covers the basic knowledge of SQL JOINs, with additional articles and other resources on our platform.

GROUP BY

The GROUP BY clause, paired with aggregate functions, is fundamental in SQL for calculating statistics like counts, averages, and sums from your data. This topic is essential for any SQL interview.

Our article Top 9 SQL GROUP BY Interview Questions provides a collection of the most frequently asked interview questions about GROUP BY. Each question includes a detailed answer, making sure you're prepared to discuss these topics during an interview.

If you are looking for an intermediate-level practice of GROUP BY topics, we recommend our Creating Basic SQL Reports course. It offers 100 exercises that focus on nuances of GROUP BY that can be asked about during an interview. It’s a hands-on course where you write your own SQL queries to help you better understand the issues and commit them to memory.

Furthermore, our article GROUP BY and Aggregate Functions: A Complete Overview gives a thorough explanation of GROUP BY and aggregate functions. This comprehensive guide is an excellent resource to round out your study, ensuring you have a robust understanding of how these functions work and how they can be applied in various scenarios.

Data Analysis in SQL

We know that many of our users work specifically in the domain of data analysis. For these users, we have prepared an article 25 SQL Interview Questions for Data Analysts, which collects common SQL interview questions that can be asked for a role of data analyst. The article covers intermediate and advanced topics, like CTEs or window functions.

Window Functions

Window functions are an advanced SQL topic. Window functions are particularly useful when writing complex reports in SQL. For this reason, they are essential in data analysis and will come up in any data analysis interview.

Our article Top 10 SQL Window Functions Interview Questions contains the most common interview questions you might encounter regarding window functions. Each question has a detailed answer and links to further resources to help you dive deeper into each topic.

For those looking to refresh their knowledge through practice, we recommend our specialized courses:

• Window Functions – Covers the entire syntax of SQL window functions through interactive, hands-on exercises, making it ideal for those new to window functions or needing a refresher.
• Window Functions Practice Set- Aimed at those already familiar with window functions, this course provides additional practice to help refine your skills and prepare for more complex interview questions.

Additionally, we recommend our Window Functions Cheat Sheet, a handy quick reference guide for window functions. For a more thorough review, SQL Window Functions Guide is a comprehensive article that covers the basics of window functions with links to additional resources.

Common Table Expressions

Common Table Expressions, or CTEs, is another advanced topic crucial for SQL interviews. CTEs help you organize and manage long and complex queries, make writing complex reports easier, and help you query hierarchical structures through recursive queries.

Our article Top 5 SQL CTE Interview Questions compiles essential CTE-related questions you're likely to face in interviews.in an article. Each question in the article is paired with a detailed answer to help you understand what is the most important in each response.

We also recommend our interactive Recursive Queries course that covers the syntax of CTEs through practice. The course is designed to teach the syntax and use of CTEs, including recursive CTEs, through hands-on exercises.

Advanced SQL

Finally, check out these articles to help you get ready for an advanced SQL interview:

• How to Prepare for an Advanced SQL Interview
• Top 27 Advanced SQL Interview Questions with Answers
• 15 Tricky SQL Interview Questions for Experienced Users

We also suggest our Advanced SQL Practice track, which is an online series of SQL practice courses designed for advanced users.

Good Luck with Your Interview!

In this article we have gathered over 100 SQL interview questions and 20 additional resources compiled here to ensure you're thoroughly prepared. To further enhance your preparation, we recommend our All Forever SQL Package. It provides access to all our current and future courses in a single purchase, making it an excellent investment for your ongoing SQL education and interview readiness.

Sign up for free at LearnSQL.com and explore our SQL courses offer. Each month, we offer one of our courses—typically a practical, hands-on course—for free. This gives you a perfect opportunity to try out our resources without any commitment and see how they can help you succeed in your SQL interview. Take advantage of these offers to boost your confidence and sharpen your SQL skills effectively.