This book has been invaluable to me for creating databases for use with web sites. It seems to cover all the commands I need including refreshers on things like left joins, right joins, left outer joins, and when to use them. This version covers MySQL 4, and the more current MySQL version is 5.x. Still many hosting companies may still only support MySQL 4.x so this book is still useful for those sites. Heck, my host only recently upgraded for 3.x to 4.x! If you can buy only one book this is the one for you. It even covers the C API, Perl DBI API and PHP API. I can't say I've used those chapters though since I have separate books for those topics. Still the chapters on Query optimization and various SQL syntax are succinct and easy to understand.