This is an interactive book which aims to be the best place on the internet for learning SQL.
Free

Description

Each chapter is designed to take about 30 minutes. It is free of charge, free of ads and doesn't require registration or downloads. It helps you learn by running queries against a real-world dataset to complete projects of consequence. It is not a mere reference page — it conveys a mental model for writing SQL.

More Resources & Tools in Learn Software Testing

Automated Software Testing...

Unit Testing, Coverage Criteria and Design for Testability.

How to Make Software Fail

Learn how to catch bugs and break software as you discover different testing methods that will help you build better software.

Principles of chaos engineering

Chaos Engineering is the discipline of experimenting on a system in order to build confidence in the system’s capability to withstand turbulent conditions in production.