I have used SQL for a couple years and thought I knew all I needed to know. This book shows you everything! You learn all aspects of SQL including designing and creating databases right down to finding out if your doing an inner or outer join. An excellent book I would recommend to anyone needing to learn SQL for any reason. You can learn as much or as little as you need. And the knowledge will stick with you. It does need a few more code examples but the logic is there explaining anything you need to understand. I started using the things I learned in this book immediately in my job. Great book!