oracle里如何将两个日期的时间差返回**时**分的格式

SELECT
EXTRACT(DAY FROM (sysdate-to_date('2012-03-29 00:00:00','YYYY-MM-DD HH24:MI:ss')) DAY TO SECOND )
|| ' days '
|| EXTRACT(HOUR FROM (sysdate-to_date('2012-03-29 00:00:00','YYYY-MM-DD HH24:MI:ss')) DAY TO SECOND )
|| ' hours'
|| EXTRACT(MINUTE FROM (sysdate-to_date('2012-03-29 00:00:00','YYYY-MM-DD HH24:MI:ss')) DAY TO SECOND )
|| ' minute'
|| EXTRACT(SECOND FROM (sysdate-to_date('2012-03-29 00:00:00','YYYY-MM-DD HH24:MI:ss')) DAY TO SECOND )
|| ' second' "Interval"
FROM DUAL;

SELECT
EXTRACT(DAY FROM (sysdate-to_date('2013-09-01 00:00:00','YYYY-MM-DD HH24:MI:ss')) DAY TO SECOND )*24+
EXTRACT(HOUR FROM (sysdate-to_date('2013-09-01 00:00:00','YYYY-MM-DD HH24:MI:ss')) DAY TO SECOND )
|| ' hours'
|| EXTRACT(MINUTE FROM (sysdate-to_date('2013-09-01 00:00:00','YYYY-MM-DD HH24:MI:ss')) DAY TO SECOND )
|| ' minute'
|| EXTRACT(SECOND FROM (sysdate-to_date('2013-09-01 00:00:00','YYYY-MM-DD HH24:MI:ss')) DAY TO SECOND )
|| ' second' "Interval"
FROM DUAL;