Getting started:

http://www.sqlteaching.com/
https://www.codecademy.com/courses/learn-sql

Related tutorials:

MySQL-CLI: https://www.youtube.com/playlist?list=PLfdtiltiRHWEw4-kRrh1ZZy_3OcQxTn7P
Analyzing Business Metrics: https://www.codecademy.com/learn/sql-analyzing-business-metrics
SQL joins infografic: http://cd64.de/sql-joins

Tools:

DataGrip: https://www.jetbrains.com/datagrip/
Sequel Pro: http://www.sequelpro.com/

Commands
Aggregate functions
Multiple tables
Users functions
Find out the IP Address of the Mysql Host