How to script XML Schema collection in SQL Server 2012?
If I understand the Question correctly, you need to use the XML_SCHEMA_NAMESPACE built-in function to extract the Schema Collection, and you can find the list of those in the sys.xml_schema_collections system catalog view. You can use something along the lines of:

SELECT CONVERT(NVARCHAR(MAX), XML_SCHEMA_NAMESPACE(sch.[name], xsc.[name])) AS [XSD]
FROM   sys.xml_schema_collections xsc
INNER JOIN sys.schemas sch
        ON sch.[schema_id] = xsc.[schema_id]
WHERE  xsc.[xml_collection_id] &lt;&gt; 1;


I put the WHERE  xsc.[xml_collection_id] &lt;&gt; 1 filter in there to avoid getting the following error:


  Msg 6314, Level 16, State 1, Line 1
  Collection specified does not exist in metadata : 'sys'