Relational databases have become the most common data storage mechanism for modern computer applications. Programming languages such as Java, C, and COBOL, and scripting languages such as Perl, VBScript, and JavaScript must often access a data source in order to retrieve or modify data. Many of these data sources are managed by a relational database management system (RDBMS), such as Oracle, Microsoft SQL Server, MySQL, and DB2, that relies on the Structured Query Language (SQL) to create and alter database objects, add data to and delete data from the database, modify data that has been added to that database, and of course, retrieve data stored in the database for display and processing.

SQL is the most widely implemented language for relational databases. Much as mathematics is the language of science, SQL is the language of relational databases. SQL not only allows you to manage the data within the database, but also manage the database itself. By using SQL statements, you can access an SQL database directly by using an interactive client application or through an application programming language or scripting language. Regardless of which method you use to access a data source, a foundation in how to write SQL statements is required in order to access relational data. SQL: A Beginner’s Guide, Third Edition provides you with such a foundation. It describes the types of statements that SQL supports and explains how they’re used to manage databases and their data. By working through this book, you’ll build a strong foundation in basic SQL and gain a comprehensive understanding of how to use SQL to access data in your relational database.

This third edition has been updated to include the provisions of the ISO SQL:2006 standard, along with technical corrigenda published in 2007. Chapter 18 has been added to cover SQL/XML, which was added to the SQL standard in 2006. In addition, the SQL statements have been reformatted and all database object names folded to uppercase to improve readability and transportability across the wide variety of commercially available RDBMS products.