MySQL--自建分割字符串函數

 DELIMITER $$

DROP FUNCTION IF EXISTS `traffic`.`portgroup`$$
CREATE DEFINER=`root`@`*` FUNCTION  `traffic`.`portgroup`(p INT) RETURNS varchar(30) CHARSET latin1
    READS SQL DATA
BEGIN
  DECLARE a varchar(30) default '0';
  SELECT  IFNULL(groups,0) into a FROM protocol where port=p;
return a;
end;

 $$

DELIMITER ;