Online Resources

SQL

SQLBolt

https://sqlbolt.com/

SQLZoo

https://sqlzoo.net/wiki/SQL_Tutorial

SQLTutorial.org

https://www.sqltutorial.org/

Quick SQL Cheatsheet

https://github.com/enochtangg/quick-SQL-cheatsheet

SQL Cheatsheet

https://www.interviewbit.com/sql-cheat-sheet/

Geeksfor Geeks

https://www.geeksforgeeks.org/sql/sql-tutorial/

Codecademy

https://www.codecademy.com/learn/learn-sql

SQL for Data Analytics – Beginners Guide

https://github.com/amartinson193/The_Ultimate_List_of_Free_SQL_Resources/blob/main/Books/SQL%20for%20Data%20Analytics%20by%20Standford%20University.pdf

SQL Server Execution Plans

https://www.red-gate.com/simple-talk/books/sql-server-execution-plans-third-edition-by-grant-fritchey/

MySQL

MySQL Labs

https://labs.mysql.com/

Codecademy

https://www.codecademy.com/resources/docs/mysql

MySQL Books

https://www.mysql.com/why-mysql/books/

PostgreSQL

pgPedia

https://pgpedia.info/

PostgreSQL Tutorial

https://www.postgresqltutorial.com/

Tutorials Point PostgreSQL

https://www.tutorialspoint.com/postgresql/

PostgreSQL Primer for Busy People

https://zaiste.net/posts/postgresql-primer-for-busy-people/

Awesome Postgres

https://github.com/dhamaniasad/awesome-postgres

SQLite

The Definitive Guide to SQLite (2nd Edition)

http://www.apress.com/9781430232254

Using SQLite

http://shop.oreilly.com/product/9780596521196.do

Getting Started with SQL – A Hands-On Approach for Beginners

http://shop.oreilly.com/product/0636920044994.do

SQLite Home Page

https://www.sqlite.org/

GeeksforGeeks

https://www.geeksforgeeks.org/sql/introduction-to-sqlite/

Exercism

https://exercism.org/tracks/sqlite

freeCodeCamp

https://www.freecodecamp.org/news/a-brief-introduction-to-sqlite/