mysql 创建 存储函数 split_string

-- 创建存储函数
DROP FUNCTION IF EXISTS SPLIT_STR; -- 判断是否存在，存在则删除
CREATE FUNCTION SPLIT_STR(
x VARCHAR(255),
  delim VARCHAR(12),
  pos INT
) RETURNS VARCHAR(255)
DETERMINISTIC
BEGIN
   RETURN REPLACE(SUBSTRING(SUBSTRING_INDEX(x, delim, pos),
       LENGTH(SUBSTRING_INDEX(x, delim, pos -1)) + 1),
       delim, ‘‘);
END;

SELECT split_str(‘7654,7698,7782,7788‘,‘,‘,1) as one,
split_str(‘7654,7698,7782,7788‘,‘,‘,2) as two,
split_str(‘7654,7698,7782,7788‘,‘,‘,3) as three,
split_str(‘7654,7698,7782,7788‘,‘,‘,4) as forms