Mysql查询结果作为另一张表的更新内容

DELIMITER $$    
DROP FUNCTION IF EXISTS `func_splitString` $$    
CREATE FUNCTION `func_splitString`    
( f_string VARCHAR(1000),f_delimiter VARCHAR(5),f_order INT)   
  RETURNS VARCHAR(255) CHARSET utf8    
BEGIN    
    DECLARE result VARCHAR(255) DEFAULT '';    
    SET result = REVERSE(SUBSTRING_INDEX(REVERSE(SUBSTRING_INDEX(f_string,f_delimiter,f_order)),f_delimiter,1));    
    RETURN result;    
END$$  

//更新表字段3min_document：cover_id int
//查询表字段3min_document_video:video string (内容类似：xxxxxxx|12)
UPDATE 3min_document d INNER JOIN 3min_document_video v ON d.id=v.id
SET d.cover_id=func_splitString(v.video,'|',2);

INSERT INTO `rooms` (`name`,`phone`,`password`)
SELECT `hostName`,`hostTel`,`hostPaw` FROM `t_hostel` ORDER BY `hostName`;