鉴于：
INSERT INTO EP_ACCESS (START_TIMESTAMP, DISCONNECT_TIMESTAMP)
VALUES (TO_DATE('2020-01-01 00:00:01','yyyy/mm/dd hh24:mi:ss'), TO_DATE('2020-01-01 00:01:00','yyyy/mm/dd hh24:mi:ss'));
和：
SELECT SUM(E.Start_timestamp-E.Disconnect_timestamp) AS WATCHING_TIME
FROM EP_ACCESS
如何将所选内容转换为小时、分钟和秒？