The book "PostgreSQL 8.4 Official Documentation - Volume I. The SQL Language" is the part of the official documentation for PostgreSQL 8.4.

To make the large amount of information about PostgreSQL manageable, this information has been organized in several volumes. Each volume is targeted at a different class of users, or at users in different stages of their PostgreSQL experience:

Volume I consists from:

• Part I - is an informal introduction for new users.
• Part II - documents the SQL query language environ- ment, including data types and functions, as well as user-level performance tuning. Every PostgreSQL user should read this.