SQL Guide
Welcome to the SQL User Guide. This section is designed to help you build a solid understanding of SQL, focusing on thinking in queries and working with real schemas without diving into database internals.
Getting started
New to SQL? Start here! Learn what SQL is, how it differs from other tools, and the fundamental mental models you'll need.
Querying data
Learn the core skill of SQL: writing queries to retrieve and filter data from your database.
Relationships & joins
Master one of SQL's most powerful features: combining data from multiple tables.
Modifying data
Learn how to insert, update, and delete data safely and effectively.
Advanced querying
Take your queries to the next level with subqueries and common table expressions.
SQL in practice
Connect SQL to your application code and understand how it fits into real-world development.