项目有通过一批ID去过滤结果的需求，因为这个ID是从其他平台拉下来的excel，为了避免加引号逗号的麻烦，在mysql存储过程里面拼接。在此做个记录。很多地方用得上。

1.通过某个字符，分割字符串的函数。输入分别为f_string(待分割字符串),f_delimiter(分割字符),f_order(取的字符串的index)

DELIMITER $$USE `money`$$DROP FUNCTION IF EXISTS `F_SPLIT_STRING`$$CREATE DEFINER=`root`@`%` FUNCTION `F_SPLIT_STRING`(f_string VARCHAR(1000),f_delimiter VARCHAR(5),f_order INT) RETURNS VARCHAR(255) CHARSET utf8BEGIN  DECLARE result VARCHAR(255) DEFAULT '';  SET result = REVERSE(SUBSTRING_INDEX(REVERSE(SUBSTRING_INDEX(f_string,f_delimiter,f_order)),f_delimiter,1));  RETURN result;END$$DELIMITER ;

2.要循环取分割出来的字符串就得知道分割出来多少个字符串

SELECT LENGTH(APPSFLYERID) - LENGTH(REPLACE(APPSFLYERID, '\n', '')) + 1 INTO @APPSFLYERID_CNT;

3.处理一串以n分割的字符串，把它们加上分号和逗号。

'1518393292248-99576341518404097075-85687161518392385006-9013409'转换成'1518393292248-9957634','1518404097075-8568716','1518392385006-9013409'

DELIMITER $$USE `money`$$DROP PROCEDURE IF EXISTS `P_GET_ROI_BY_APPFLYER_ID`$$CREATE DEFINER=`root`@`%` PROCEDURE `P_GET_ROI_BY_APPFLYER_ID`(IN STAT_DATE VARCHAR(32),IN DAY_CNT INT,IN APPSFLYERID MEDIUMTEXT)BEGIN    SET @APPSFLYERID_STR = "";    SET @TEMP_ID = "";    SELECT LENGTH(APPSFLYERID) - LENGTH(REPLACE(APPSFLYERID, '\n', '')) + 1 INTO @APPSFLYERID_CNT;        SET @i = 1;    WHILE @i <= @APPSFLYERID_CNT DO    SELECT F_SPLIT_STRING(APPSFLYERID,"\n",@i) INTO @TEMP_ID;    IF @i = 1 THEN    SET @APPSFLYERID_STR = CONCAT("'",@TEMP_ID,"'");    ELSE    SET @APPSFLYERID_STR = CONCAT(@APPSFLYERID_STR,",'",@TEMP_ID,"'");    END IF;     SET @i = @i + 1;    END WHILE;    SELECT   @APPSFLYERID_STR;END$$DELIMITER ;