Structured query language (SQL) is the preferred language for relational database management systems such as Sybase, Microsoft SQL Server, Access, and others. In addition, SQL commands are used to update, manipulate, and retrieve data from a database. 

As relational databases become more prevalent across many industries, including marketing and sales, new groups of professionals are interested in learning SQL. Furthermore, SQL knowledge is no longer limited to data engineers.

There is already a wealth of free information online that can instruct beginners in the fundamentals of SQL.

Here are the five best free SQL learning resources.

SQLZoo

SQLZoo is a Wiki-based interactive tutorial that provides SQL lessons and projects for beginners. Students begin with fundamental functions like COUNT, SUM, and AVG and progress to intermediate projects.

The lessons in SQLZoo are built around self-explanatory interactive coding challenges. This tutorial is an excellent resource for students who want to learn SQL through small, straightforward exercises.

SQL for Web Nerds

This course is more of an advanced level class; you will learn the nitty-gritty details of SQL in this class. Philip Greenspun, a professor at MIT, was the one who developed it. The website isn't particularly flashy but provides appropriate content for experts.

PostgreSQL Exercises

PostgreSQL is a database management system that is among the most popular on the planet. This platform offers you various exercises to gauge your proficiency with SQL and PostgreSQL in light of this.

SQL Bolt

This platform is a series of engaging exercises that provide a foundational understanding of SQL. This tutorial is a helpful resource for those who are just starting and want to brush up on their previous learning.

Codecademy

The course is structured as a series of interactive coding tutorials that guide students from the fundamental functionality to various extensive projects. The vast repository of Codecademy's exercises and the service's sleek interface make for a seamless learning experience. This tutorial is suitable for students who desire a more professional learning environment.