Larry Ullman's Visual QuickStart Guide is top-notch. At the beginning of the summer, I knew nothing about MySQL. Now I am SELECT-ing, INSERT-ing, and doing all other sorts of MySQL like a pro, or at least like someone who understands what is going on.
This book is divided into 3 major sections in my mind. The first 100 or so pages deal with installing MySQL, creating databases, and using SQL queries to do thing. The next 80 pages are about using MySQL in conjunction with various languages: PHP, Perl, and Java. The last 100 pages have helpful solutions (how to make a search engine, or present result pages when doing a search), a section on MySQL administration, and some useful appendicies.
Like most QuickStart Guides, you can jump around in this book and use it as a reference manual, though you really need to read from chapter 2 to 4 if you are new to relational databases in general or MySQL in particular.
Chapter 3 on Database Design is excellent. I walked through it step-by-step and followed the instructions to plan out my database. The database has been working very well, and I felt that I really understood what was going on instead of just entering commands and hoping they worked.
Chapter 4 and 5, which explain MySQL commands and functions, are likewise very well done and useful.
My only criticism is that sometimes the code presented in the latter sections of the book gets mired-down in lots of HTML tags which can make things a little difficult to read.
There is not much here for fairly intermediate to advanced users who already know MySQL. If that is you, perhaps another book would serve you better.
In summary: if you want to understand and use MySQL and have little to no knowledge of it currently, this book is for you.