Functions on Nodes - local-name
Applies to: 
SQL Server
Returns the local part of the name of $arg as an xs:string that will either be the zero-length string or will have the lexical form of an xs:NCName. If the argument is not provided, the default is the context node.
Syntax
fn:local-name() as xs:string
fn:local-name($arg as node()?) as xs:string
Arguments
$arg
Node name whose local-name part will be retrieved.
Remarks
In SQL Server, fn:local-name() without an argument can only be used in the context of a context-dependent predicate. Specifically, it can only be used inside brackets (
[ ]).If the argument is supplied and is the empty sequence, the function returns the zero-length string.
If the target node has no name, because it is a document node, a comment, or a text node, the function returns the zero-length string.
Examples
This topic provides XQuery examples against XML instances that are stored in various xml type columns in the AdventureWorks database.
A. Retrieve local name of a specific node
The following query is specified against an untyped XML instance. The query expression, local-name(/ROOT[1]), retrieves the local name part of the specified node.
declare @x xml
set @x='<ROOT><a>111</a></ROOT>'
SELECT @x.query('local-name(/ROOT[1])')
-- result = ROOT
The following query is specified against the Instructions column, a typed xml column, of the ProductModel table. The expression, local-name(/AWMI:root[1]/AWMI:Location[1]), returns the local name, Location, of the specified node.
SELECT Instructions.query('
declare namespace AWMI="https://schemas.microsoft.com/sqlserver/2004/07/adventure-works/ProductModelManuInstructions" ;
local-name(/AWMI:root[1]/AWMI:Location[1])') as Result
FROM Production.ProductModel
WHERE ProductModelID=7
-- result = Location
B. Using local-name without argument in a predicate
The following query is specified against the Instructions column, typed xml column, of the ProductModel table. The expression returns all the element children of the <root> element whose local name part of the QName is "Location". The local-name() function is specified in the predicate and it has no arguments The context node is used by the function.
SELECT Instructions.query('
declare namespace AWMI="https://schemas.microsoft.com/sqlserver/2004/07/adventure-works/ProductModelManuInstructions" ;
/AWMI:root//*[local-name() = "Location"]') as Result
FROM Production.ProductModel
WHERE ProductModelID=7
The query returns all the <Location> element children of the <root> element.