不允许从触发器返回结果集

Question

这是我的触发器：

CREATE DEFINER=`root`@`localhost`
 TRIGGER `far_c` AFTER INSERT ON `far_input` FOR EACH ROW
 BEGIN
 CALL far_calculator('2', '3', '4','',''); 
END

和我的存储过程

 CREATE DEFINER=`root`@`localhost` 
PROCEDURE `far_calculator`(IN `len` INT(11), IN `bre` INT(11), IN `wid` INT(11), OUT `site_area` FLOAT, OUT `far_val` FLOAT) DETERMINISTIC CONTAINS SQL SQL SECURITY DEFINER 
BEGIN 
select length*breadth into site_area from far_input where length=len and breadth=bre ; 
select far_value into far_val FROM far_master where site_area between far_site_min and far_site_max;
 select far_val*site_area as far_area;
 END

当我运行触发器时，我收到以下错误。