<xs:group name="query_expressions">
  <xs:annotation>
    <xs:documentation xml:lang="en">query expressions. this group is used for documentation only, not used in XML file.</xs:documentation>
  </xs:annotation>
  <xs:all>
    <xs:element ref="row_value_constructor"/>
    <xs:element ref="row_value_expression"/>
    <xs:element ref="table_value_constructor"/>
    <xs:element ref="table_expression"/>
    <xs:element ref="from_clause"/>
    <xs:element ref="table_reference"/>
    <xs:element ref="joined_table"/>
    <xs:element ref="where_clause"/>
    <xs:element ref="group_by_clause"/>
    <xs:element ref="having_clause"/>
    <xs:element ref="window_clause"/>
    <xs:element ref="query_specification"/>
    <xs:element ref="query_expression"/>
    <xs:element ref="search_or_cycle_clause"/>
    <xs:element ref="subquery"/>
  </xs:all>
</xs:group>