<extract_source xmlns="http://www.sqlparser.com/xml/ansi2003"> <datetime_value_expression>{1,1}</datetime_value_expression> <interval_value_expression>{1,1}</interval_value_expression> </extract_source>
<xs:element name="extract_source"> <xs:complexType> <xs:choice> <xs:element ref="datetime_value_expression"/> <xs:element ref="interval_value_expression"/> </xs:choice> </xs:complexType> </xs:element>