你错过了将结果乘以60一次（秒）。两个日期之差就是它们之间的天数。

SQL> with temp as
  2    (select to_date('16-SEP-23 15:08:35', 'dd-mon-yy hh24:mi:ss') -
  3            to_date('16-SEP-23 15:08:14', 'dd-mon-yy hh24:mi:ss') diff
  4     from dual
  5    )
  6  select diff as days,
  7    diff * 24 as hours,
  8    diff * 24 * 60 as minutes,
  9    diff * 24 * 60 * 60 as seconds
 10  from temp;

      DAYS      HOURS    MINUTES    SECONDS
---------- ---------- ---------- ----------
,000243056 ,005833333        ,35         21

如果你切换到时间戳，事情变得更加明显;两个时间戳的差值是 interval day to second，然后从中提取任何你想要的东西：

SQL> with temp as
  2    (select to_timestamp('16-SEP-23 15:08:35', 'dd-mon-yy hh24:mi:ss') -
  3            to_timestamp('16-SEP-23 15:08:14', 'dd-mon-yy hh24:mi:ss') diff
  4     from dual
  5    )
  6  select diff int_day_to_sec,
  7    extract (hour from diff) as hours,
  8    extract (minute from diff) as minutes,
  9    extract (second from diff) as seconds
 10  from temp;

INT_DAY_TO_SEC                      HOURS    MINUTES    SECONDS
------------------------------ ---------- ---------- ----------
+000000000 00:00:21.000000000           0          0         21