There are a number of irratating errors in this book, but they're all addressed at <www.osborne.com/products/ 0072195371/0072195371_errata.doc>.
I've used this book, and the ExamCram2 9i 1Z0-007 book, and would recommend this book over the first, for two reasons. 1) The example schema (Scott) used thoughout the book is less (unnecessarily?) complex and is shipped with Oracle and is therefore much closer to what you're likely to encounter in the exam. 2) Although the Couchman book is much bigger, it's explanations seem much clearer - compare how smoothly (outer) joins and group functions are introduced in Couchman vs Examcram2.
That said, I like the examcram2 book, and it's likely to stay on my desk as a quick reference anyway...