SQLI-labs
Platform to learn SQL injection. Covers error-based (union select, double injection), blind (boolean and time-based), update/insert and header injections, second-order injection, WAF bypass, and more for GET and POST scenarios.
Notes
Default DB credentials in install: root:toor (Backtrack). Run setup/reset DB from browser. Walkthroughs at dummy2dummies.blogspot.com, securitytube.net; book at leanpub.com/SQLI-LABS.