XQuery 1.0: An XML Query Language

XML is a versatile markup language, capable of labeling the information content of diverse data sources including structured and semi-structured documents, relational databases, and object repositories. A query language that uses the structure of XML intelligently can express queries across all these kinds of data, whether physically stored in XML or viewed as XML via middleware. This specification describes a query language called XQuery, which is designed to be broadly applicable across many types of XML data sources.

This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited from another document. W3C’s role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web.This document incorporates minor changes made against the Proposed Recommendation of 21 November 2006; please see the public disposition of comments for details. Changes to this document since the Proposed Recommendation are detailed in the J Revision Log.

Please report errors in this document using W3C’s public Bugzilla system. It will be very helpful if you include the string “[XQuery]” in the subject line of your report, whether made in Bugzilla or in email. Each Bugzilla entry and email message should contain only one error report.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

source: http://www.w3.org/TR/xquery/