You can't expect to master a skill if you only know one side of it. Learn what goes into building and configuring databases, provisioning users, and get hands on experience with the most common queries. Understanding these concepts is critical to attaining advanced level SQL Injection capabilities.
Companion repository: https://gitlab.com/r00k/sql_for_hackers
Installing SQL video: https://www.youtube.com/watch?v=miaKc0e2qyI
Chapters
-------------------------------------
00:00 Intro
00:36 Initial setup recap
01:53 Connecting to the database with mysql client
03:25 SQL database structure
05:35 SQL syntax and setting up the database
11:39 Running a sql script against the database
13:24 Using the INSERT command
14:37 Getting data with the SELECT query
15:50 Better targeting with the WHERE clause
20:45 Updating records with...UPDATE
22:09 Removing records with DELETE
22:57 The great and powerful UNION SELECT
25:06 Modifying the displayed output with ORDER and LIMIT
