OneCompiler

SQL

Learn SQL by writing real queries. Short lessons on every core concept, each followed by exercises you solve right in the editor.

7 sections·41 items·Beginner
This course includes
  • 50 coding problems with test cases
  • 41 lessons
  • Free — runs in your browser, no setup

What you'll learn

Read and filter data with SELECT, WHERE and ORDER BY
Summarize data with GROUP BY and aggregate functions
Insert, update and delete records
Combine data from multiple tables with joins
Work with keys, constraints, views and indexes

Syllabus

About this course

SQL is the language of relational databases, and the fastest way to learn it is to write queries against real tables. That's how this course works: each topic starts with a short lesson, then hands you an exercise with a table already set up so you can try it immediately.

You'll start with reading data — SELECT, WHERE, sorting and filtering — then move on to aggregate functions, changing data, joins, and finally constraints, views and indexes. Quick quizzes along the way check that the ideas stick.

No setup and nothing to install. The editor runs your queries against a MySQL database and checks the results for you. If you've never touched a database before, start at the top and work down; if you know the basics, jump straight to the topic you need.