.XQUERY file extension

This is the basic program to work with .XQUERY extension

Altova XMLSpy

Altova XMLSpy XML Query Language

Altova XMLSpy is the industry’s best-selling XML editor and XML development environment for modeling, editing, transforming, and debugging XML technologies. In addition to the world’s leading XML editor, XMLSpy includes a powerful graphical XML Schema editor that allows you to design complex schemas with ease... (more)

The program works with the following extensions: xml, xq, fo, mml, vml, dtd, wml, xdr, xsd, xql, biz, tsd, mtx, tld, jsp, cml, dcd, xsl, ent, rdf, svg, spp, vxml, wsdl, xslt, rels, smil, math, xhtml and xquery

.XQUERY extension is also supported by the following programs:

Oxygen XML Editor

Oxygen XML Editor XQuery Document

Edit, convert, and debug XML databases, files, and servers.
<oXygen/> XML Editor

XML Editor XQuery Document

Stylus Studio

Stylus Studio

Stylus Studio 2006 XML Enterprise Edition is an advanced XML IDE.
XMLSPY 5 Enterprise Edition

XMLSPY 5 Enterprise Edition XML Query Language