mysqlGROUP_CONCAT结果是blob类型的，怎么转换成varchar:mysqlblob select faudit_main_id,GROUP_CONCAT( CONCAT('[', CONCAT_WS('&',FAUDIT_SUB_INDEX, FAUDIT_SRC_FIELD,FAUDIT_DST_FIELD,FAUDIT_ISKEY, FAUDIT_OPT), ']') ) sub_descfrom MIG_AUDITF_SUBgroup by faudit_main_id