How-to...
   ... Create a Return Type
   ... Add a Complex Child Element to a Return Type
   ... Check Namespaces in Return Types
   ... Create Conditional Elements in Return Types
   ... Add a Where Clause to a Query
   ... Use the Source Editor

Reference
   XQuery Language Version Support
   Built-in XQuery Functions

Related Topics
    How-to...
    ... Create Your First Data Services
    ... Test a Read Function and Simple Update
    ... Test a Create or Delete Procedure
    ... How To Develop Good XQSEs

   Concepts...
   Understanding Data Service Annotations

   Reference...
   XQuery Scripting Extensions