查询父id下所有子集

BEGIN
DECLARE sTemp TEXT;
DECLARE sTempChd TEXT;
SET sTemp = '\'\'';
SET sTempChd = rootid;
WHILE sTempChd IS NOT NULL DO
SET sTemp = CONCAT(sTemp,',',sTempChd);
SELECT GROUP_CONCAT(id) INTO sTempChd FROM hzs WHERE FIND_IN_SET(pid,sTempChd)>0;
END WHILE;
RETURN sTemp;
END