mysql 更具父类id 查询所有子类id

//创建函数
CREATE FUNCTION getChildeIds(rootId INT)
RETURNS VARCHAR(1000)
BEGIN
DECLARE sTemp VARCHAR(1000);
DECLARE sTempChd VARCHAR(1000);

      SET sTemp = '0';
     SET sTempChd =cast(rootId as CHAR);

     WHILE sTempChd is not null DO
        SET sTemp = concat(sTemp,',',sTempChd);
         SELECT group_concat(子ID) INTO sTempChd FROM  你的表 where FIND_IN_SET(父id,sTempChd)>0;
   END WHILE;
   RETURN sTemp;

END

// 应用
select getChildeIds(1);