SQLi Lab 系列的文字和视频（需要翻墙），讲解的很好
SQLi Lab Series - Introduction
SQLi Lab Series - Error Based
SQLi Lab Series - Double Query / SubQuery
SQLi Lab Series - Blind Injection - Boolean Based
SQLi Lab Series - Blind Injection - Time Based
SQLi Lab Series - Using Outfile / Dumpfile
SQLi Lab Series - Post Based
SQLi Lab Series - Double Query
SQLi Lab Series - Update Query
SQLi Lab Series - Insert Query / Headers
SQLi Lab Series - Cookie Based
Second Order Injection
Bypassing blacklist filters (Part 1)
Bypassing blacklist filters (Part 2)
Bypassing Blacklist Filters (Part 3)
Bypassing Waf Techniques -- Setting Up Tomcat
Bypassing Waf Techniques -- Impedance Mismatch
Bypassing Addslashes - Charset Mismatch
The whole series of the video of SQLi Lab Series