SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    QualifiedAsterisk (children 1)
     Identifier X
    QualifiedAsterisk (children 1)
     Identifier s
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier X
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (alias s) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 1)
           Asterisk
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier X
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier X.x_b
        Identifier s.x_b
   ExpressionList (children 6)
    OrderByElement (children 1)
     Identifier X.id
    OrderByElement (children 1)
     Identifier X.x_a
    OrderByElement (children 1)
     Identifier X.x_b
    OrderByElement (children 1)
     Identifier s.id
    OrderByElement (children 1)
     Identifier s.x_a
    OrderByElement (children 1)
     Identifier s.x_b