Argument Types and Rules - Advanced SQL Engine - Teradata Database

These rules apply to the XML type instance to be validated:

• If XML_value_expr is NULL, the function returns NULL.
• If XML_value_expr is an empty sequence, the function returns an empty sequence.
• If XML_value_expr is a sequence that contains even a single item that is an atomic value, attribute node, namespace node or text node, an error is raised.