XPath Tutorial

The XPath processor allows you to retrieve a subset of an XML document. A query, which is always an XPath expression, returns a well-formed XML node-list or an XPath value object. In XPath 2.0, an expression returns a sequence of XML nodes and/or XPath value objects. This XPath tutorial covers the following topics:

About the XPath Processor, Sample Data for Examples and Testing, Getting Started with XPath Queries, Specifying the Nodes to Evaluate, Handling Strings and Text in XPath, Specifying Boolean Expressions and Functions, Specifying Number Operations and Functions, Comparing Values, Generating XPath, Finding a Particular Node, Obtaining a Union, Obtaining Information About a Node or a Node Set, Using XPath Expressions in Stylesheets, Accessing Other Documents During Query Execution, XPath Quick Reference.

http://www.stylusstudio.com/docs/v2006/d_xpath.html