SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier summing
   ExpressionList (children 3)
    OrderByElement (children 1)
     Identifier x
    OrderByElement (children 1)
     Identifier y
    OrderByElement (children 1)
     Identifier z
