XML Query Language (XQuery) is a query and programming language for processing XML documents and data. XML data and other databases that store data in a format analogous to HTML can be processed with XQuery. The main objective of XQuery is to provide query mechanisms for data extraction from real and virtual Web based documents. It aims to link Web and database technologies with the help of eXtensible Markup Language (XML).
The World Wide Web (WWW) Consortium is responsible for framing XQuery 1.0.
Source: https://www.techopedia.com/definition/2671/xml-query-language-xquery