Functions Related to QNames - namespace-uri-from-QName
Applies to: 
SQL Server
Returns a string representing the namespace uri of the QName specified by $arg. The result is the empty sequence if $arg is the empty sequence.
Syntax
namespace-uri-from-QName($arg as xs:QName?) as xs:string?
Arguments
$arg
Is the QName whose namespace URI is returned.
Examples
This topic provides XQuery examples against XML instances that are stored in various xml type columns in the AdventureWorks database.
A. Retrieve the namespace URI from a QName
For a working sample, see local-name-from-QName (XQuery).
Implementation Limitations
These are the limitations:
- The namespace-uri-from-QName() function returns instances of xs:string instead of xs:anyURI.