Learn SQL online, from beginner to advanced
Master SQL with structured, hands-on courses. Real code examples, practical exercises, and professional mentorship.
Built for practical SQL learning
Not another theory dump. Every lesson has real SQL you can run and real results you can see.
Real code examples
Every lesson includes syntax-highlighted SQL with actual query results. Copy, paste, run.
Structured path
3 courses, 26 chapters, 79 topics. Beginner to advanced in a logical progression.
1-on-1 mentorship
Need personal guidance? Work directly with an SQL professional who adapts to your pace.
No signup required
All courses are free and open. No registration, no email, no paywall. Just start reading.
Choose your starting point
Each course builds on the previous one, but you can jump in at any level.
SQL Beginner
SQL Intermediate
SQL Advanced
Practice, reference and compare
Beyond the courses: a full interview prep portal, hands-on exercises, and reference libraries for functions, errors, tools and databases. All free, no signup.
SQL Interview Questions
120 questions across 8 categories, from basic to advanced, each with a diagram and runnable SQL.
Start prepping →SQL Exercises
45 practice problems, easy to hard, with schema, sample data, expected result, solution and explanation.
Solve problems →SQL Functions Library
Every SQL function explained with syntax, runnable examples, common mistakes and performance notes.
Browse functions →SQL Server Error Library
Look up any SQL Server error by number: what it means, why it happens, examples and how to fix it.
Fix an error →SQL Tools Directory
Honest reviews of SSMS, Azure Data Studio, DBeaver, DataGrip, pgAdmin and more, with pros and cons.
Compare tools →SQL Comparisons
Head to head: SQL Server vs PostgreSQL, MySQL vs PostgreSQL, SQL vs NoSQL and more, with a clear verdict.
See comparisons →SQL Playground
Run SQL in your browser on SQLite or PostgreSQL with sample data, open your own SQLite file, or format a query.
Open the playground →Install & Setup Guides
Install SQL Server, PostgreSQL, MySQL and more, run them in Docker, back them up and migrate between them.
Set up a database →Cloud Databases
Managed databases on AWS, Azure and Google Cloud, plus Supabase and Neon: features, limits and dated pricing.
Compare cloud options →From zero to SQL pro
Pick a course
Choose Beginner, Intermediate, or Advanced based on your current knowledge.
Read & practice
Work through chapters with real SQL examples. Run the code on your own database.
Build skills
Each chapter builds on the last. By the end, you can design and optimize real databases.
Get help
Stuck? Book a 1-on-1 mentorship session or use our SQL development services.
Built for every SQL learner
Students
Preparing for tech interviews or database coursework? Build a solid SQL foundation.
Data analysts
Write better queries, build dashboards, and extract insights from any database.
Developers
Understand what happens behind the ORM. Optimize queries and design schemas.
Professionals
Business analysts, PMs, and managers who need to query data without waiting for IT.
Ready to write your first query?
Start with the basics and work your way up. No signup, no payment, no excuses.