触发器中不允许返回结果集，解决方法是顶一个变量，然后将返回值返回给变量。

		
DROP TRIGGER IF EXISTS `test`.`demo_AFTER_INSERT`;

DELIMITER $$
USE `test`$$
CREATE DEFINER=`root`@`%` TRIGGER `test`.`demo_AFTER_INSERT` AFTER INSERT ON `demo` FOR EACH ROW
BEGIN
	set @rev = "";
	SELECT 
    OUT2FILE('/tmp/demo.log',
            CONCAT_WS(',',
                    NEW.id,
                    NEW.name,
                    NEW.sex,
                    NEW.address))
	INTO @rev;
END$$
DELIMITER ;