Objectives of This Book

The single most important objective of this book is to help you harness the power of Oracle SQL to the maximum extent possible. You will learn to:

• Understand the features and capabilities of the SQL language, as implemented by Oracle.

• Use complex SQL features, such as outer joins, correlated subqueries, hierarchical queries, grouping operations, and analytical queries.

• Use DECODE and CASE to implement conditional logic in your SQL queries.

• Write SQL statements that operate against partitions, objects, and collections, such as nested tables and variable arrays.

• Use the new SQL features introduced in Oracle Database 10g, such as regular expressions and interrow calculations.

• Use best-practices to write efficient, maintainable SQL queries.

One topic that is important to us and many of our readers, but which is not explicitly discussed in this book is SQL tuning. Tuning tips are sprinkled throughout the book, but we do not include a chapter on tuning for the following reasons:

• Tuning is a large topic, and reasonable coverage of SQL tuning would easily double or triple the size of this book.

• There are already many excellent Oracle-specific and general-purpose tuning books on the market, whereas there are very few books (in our opinion, exactly one) that thoroughly explore the feature set of Oracle SQL.

• In many ways, mastery of Oracle's SQL implementation is the most important tool in your tuning toolkit.

With this book under your belt, you will be less likely to write SQL statements that perform badly, and you will be able to employ multiple strategies to rework existing statements.