Book excerpt: This Study Guide is targeted at IT professionals who are looking to become an Oracle Database Certified SQL Expert. The book provides information covering all of the exam topics for the Oracle Expert exam: "1Z0-047: Oracle Database SQL Expert." This book has been updated to include the topics added to the exam for 12c. The books in the Oracle Certification Prep series are built in lockstep with the test topics provided by Oracle Education's certification program. Each book is intended to provide the information that will be tested in a clean and concise format. The guides introduce the subject you'll be tested on, follow that with the information you'll need to know for it, and then move on to the next topic. They contain no drills or unrealistic self-tests to bump the page count without adding value. The series is intended to provide a concentrated source of exam information that is compact enough to be read through multiple times. This series is ideal for experienced Oracle professionals that are familiar with the topic being tested, but want a means to rapidly reinforce their existing skills and bridge any gaps in their knowledge. It is also an excellent option as a second source of information for candidates pursuing certification.