What is SQL?
SQL, short for Structured Query Language, is the standard language for communicating with relational databases.
It's a relatively simple language as far as coding goes, but it's also incredibly powerful.
You can write SQL statements to retrieve specific data from large databases, update data on a database, and much more. Relational database management systems like MySQL, Oracle, Microsoft SQL Server, Sybase, and Ingres use SQL.
Why should you learn SQL?
In our data-hungry world, the ability to successfully work with data is becoming more and more valuable. It's an in-demand skill and not just for data analysts. Financial teams, programmers, and even non-technical people in marketing, sales, and other functions can all benefit from understanding what it takes to extract the data they need from a large database.
You don't necessarily need to become a SQL all-star, but understanding the basics will teach you how to ask better data-related questions (at the very least).
What are the best free SQL resources available online?
SQL is a popular language and you’ll have a variety of courses, tools, and other resources to choose from as you learn and practice.
Free SQL courses
If you want a structured SQL course, here are some of the most popular free courses for learning SQL.
Codecademy's free SQL class includes four beginner-friendly lessons, five practice projects, and four quizzes to test your learnings. It covers all of the essential skills for database communication, so you'll learn how to manipulate data and create queries that communicate with more than one table.
The course helps newbies understand SQL basics in a fun and easy way, so it's a great place to start if you want to dip your toes into the world of SQL.
2. Khan Academy
Khan Academy is full of valuable free resources for all sorts of topics, including SQL.
In their Intro to SQL: Querying and managing data courses, you can learn everything from the basics to more advanced topics, like how to write advanced SQL queries using AND/OR, IN, LIKE, HAVING, and more.
Each module includes videos, challenges, and a project to test your skills.
3. Stanford University
Stanford University offers a Databases: Relational Databases and SQL course as one of their free learning options. It's a high-quality, self-paced course that takes around 16-20 hours to complete.
SQL and Databases - A Full Course for Beginners from FreeCodeCamp is a database 101 course designed for beginners, delivered as a four-hour YouTube video.
It's a solid resource if you're a complete beginner, and you'll learn everything from what a database is and other SQL basics to how to write nested queries and more.
Datacamp's Introduction to SQL Course is exactly what the title suggests – a basic, introductory look at how to use SQL.
In two hours, you'll learn how to create and query relational databases using SQL. This one isn't as comprehensive as some of the other free SQL learning resources on this list, but that may be a plus, depending on how detailed you want to go. There are seven videos in total and 24 total exercises.
SQLCourse has two course options, one for beginners and another for more advanced users.
The beginner course will teach you basic SQL commands and syntax, like how to insert, update, and delete information from tables. You can then practice inside the free online SQL interpreter.
The advanced option builds on the beginner course.
SQL lessons and tutorials
Each of these resources includes lessons that are easy to follow, plus interactive lessons for practice.
The W3Schools SQL tutorial offers short and clear lessons with relevant examples to help you learn the basics.
Like many other resources on this list, the W3Schools tutorial also has quizzes you can take to test your progress and learn from your mistakes.
SQLZoo might have a simple interface, but don't let it fool you – the exercises are easy to follow, and plenty of real-world examples help you understand the different ways to apply SQL.
You can write your SQL query, submit it, and see the results immediately. If you input the wrong answer, you'll get immediate feedback.
SQLBolt is an online resource with interactive lessons and exercises that make it easy to learn and practice SQL right in your browser. The 18 lessons will provide you with a solid baseline level of SQL knowledge.
For a unique and fun way to practice SQL, try one of these SQL-based games.
GalaXQL 3.0 takes a different approach to teaching SQL – its SQL tutorial is disguised as a galaxy manipulation application. Your virtual guide for the journey is Professor Alfred T. Guru [guu-ruu], and he does a great job of keeping things interesting and engaging.
Be sure to stick with the lessons; the galaxy map view starts to get interesting in chapter 6.
Schemaverse is a space-based strategy game implemented entirely within a PostgreSQL database.
This is a fantastic free SQL learning resource if you like gamified learning. You can compete against other players using SQL commands to control your fleet. Check out this tutorial to learn more and get started.
12. SQL Murder Mystery
Once you have the basics down, try this SQL game with a murder mystery spin.
13. SQL Police Department
Use your SQL skills to solve hypothetical crimes in SQL PD, an online crime solving game.
14. SQL Island
You’re alone on SQL Island, the only survivor of a tragic plane crash. To escape, you need to use your SQL skills to answer the game’s questions.
Free SQL practice tools
These tools are helpful SQL companion tools – use them while you complete practice quizzes, challenges, and tutorials.
15. AirOps Sidekick
Sidekick is a free A.I.-powered tool for anyone who works with SQL, whatever their skill level.
It combines A.I. and context from a data warehouse to make common SQL tasks 10x faster. You can use Sidekick wherever you work best, including inside IDEs, BI tools, consoles, and your browser.
Sidekick includes a selection of helper recipes to assist with different tasks, including writing, documenting, and fixing SQL, making it the perfect complement to your SQL learning journey.
Once you've mastered some basics, you can use SQL Fiddle to create, test, and share data structures and query results in a simple, easy-to-use interface.
SQL interview preparation
Check these websites out if you’re preparing for an interview with a SQL skills test (or you just want some extra real world practice).
HackerRank has highly recommended SQL challenges that candidates can use to prepare for job interviews (or to practice in general). You can filter the challenges by skill level and difficulty, making this a good page to bookmark and return to throughout your SQL education.
DataLemur is a platform for SQL and data analytics interview prep. It’s the interactive component to Ace the Data Science Interview, a book by Nick Singh that helps readers prepare for the Statistics, ML, and Business-Sense portions of data interviews.
SQL experts on LinkedIn, Twitter, YouTube, & more
You’ll find SQL experts to follow no matter where you prefer to hang out online.
If you want to find even more data creators to follow in addition to the few we’ve highlighted here, the Data Creators Club list is an extensive hub of helpful data-related resources.
19. LinkedIn: Nick Singh
Before creating DataLemur, Nick Singh honed his data expertise at Facebook and Google. Now, he shares his insights on data science and data science careers on LinkedIn and elsewhere. Follow him if you want to learn how to use your SQL skills to land a job in the data industry.
20. LinkedIn: Madison Schott
Her Substack newsletter, Learn Analytics Engineering, is also worth subscribing to if you’re interested in learning more about the analytics engineering field.
21. Substack: Data Analysis Journal
Once you understand the basics behind SQL, subscribe to the Data Analysis Journal from Olga Berezovsky to learn more about the practical applications of your data analytics skills.
You can follow Olga on Twitter, too.
22. YouTube: freeCodeCamp.org
This 4+ hour SQL Tutorial - Full Database Course for Beginners video from freeCodeCamp.org has racked up millions of views for a reason: It’s comprehensive, easy to understand, and perfect for beginners who aren’t sure where to start.
23. YouTube: Simplilearn
For a longer and more in-depth YouTube SQL tutorial, save this 8-hour Full SQL Course from Simplilearn.
Online communities for SQL learners
Visit these forums and communities to ask questions and get extra help with troubleshooting. They’re also a great place to ask questions about your career in data analytics.
Reddit is a fantastic resource for learning SQL – check out r/LearnSQL, a subreddit dedicated to providing users with free SQL resources. Use the search function to find tips, track down helpful advice from experienced SQL users, and other useful information. If you have a question about your SQL code that you can't find an answer to, pose it to the community.
r/SQL is another handy subreddit to bookmark for your SQL learning journey.
25. Stack Overflow
Stack Overflow's SQL questions section is an excellent place to turn to for expert advice when you have a question or can't figure out what's wrong with your SQL code.
Where to find sample data sets to practice SQL
If you're serious about learning SQL, you'll also need sample data sets. Here are three options:
Sample data sets allow you to experiment with different queries and better understand how they interact with the database, so don't skip this part.
There are tons of ways to learn SQL, so dive in!
The resources we've shared today are more than enough to kickstart your SQL career. Don't worry about choosing the perfect tool because getting started is more important.
That's one of the great things about learning SQL – there are so many free learning resources, and you can always try different tools until you find one that suits your learning style.