XQuery and XPath 2.0 shares the same data model, functions, and syntax.
XQuery Locations
XQuery shares the same data model as XPath 2.0
XQuery Operators
XQuery shares the same operators as XPath 2.0
XQuery Functions
XQuery shares the same functions as XPath 2.0
XQuery Data Types
XQuery shares the same data types as XSD (XML Schema 1.0)