We're a community-driven school of free web books and content written by people who work with data for people who work with data.
To get started check out our mission, see who's involved or dig into our completely free and growing content library of web books.
Browse Our Web BooksFeatured Chapters
Quick Introductory SQL Concepts
From Learn SQLLearn how to use SQL with your PostgreSQL database. In this interactive SQL data tutorial, get an introduction that is designed to get you querying your PostgreSQL database as quickly as possible. Learn SQL basics, tables and SQLbox.
What is a Dashboard?
From How to Design a DashboardLearn what dashboards are and why they are important to making decisions. Dashboards have a long history for supporting decision making.
SQL Join Types Explained Visually
From How to Teach People SQLData within a database exists across multiple tables, JOINs allow you to combine datasets into new tables for analysis. Learn more.