I'm Reading Larry Ullmans"PHP and MYSQL" right now. I find his style of writing easy to understand, with simple examples and good explanations. The book is $30, but is a hefty 400 plus pages and covers sql commands, PHP, and mysql as they relate to developing webpages.
Here's the book page link:
http://www.dmcinsights.com/phpmysql2/
I also read his beginners PHP book prior to reading this one. He replied to an email of mine that he considers the phpmysql book as a good follow up to the beginners php one, which after getting part way into it, I agree with.