如果要存储时间，则可以使用INTERVAL DAY(0) TO SECOND(0)数据类型（而不是字符串），然后查询可以是：

SELECT video_id,                               
       SUM(
         EXTRACT(HOUR   FROM video_duration) * 60 * 60
       + EXTRACT(MINUTE FROM video_duration) * 60
       + EXTRACT(SECOND FROM video_duration)
       ) * INTERVAL '1' SECOND AS total_duration
FROM   t_video
GROUP BY ROLLUP(video_id);

其中，对于示例数据：

CREATE TABLE t_video 
(
  video_id       NUMBER NOT NULL ENABLE, 
  video_duration INTERVAL DAY(0) TO SECOND(0), 
  object_video   VARCHAR2(1000 BYTE), 
  CONSTRAINT T_VIDEO_PK PRIMARY KEY ( VIDEO_ID )
);

INSERT INTO t_video (video_id, video_duration, object_video)
VALUES (1, INTERVAL '00:12:20' HOUR TO SECOND,'song');

INSERT INTO t_video (video_id, video_duration, object_video)
VALUES (2, INTERVAL '02:50:30' HOUR TO SECOND,'film');

输出：
| 视频_ID|总计_持续时间|
| - ------| - ------|
| 1个|+00000000 00分12秒20秒|
| 第二章|+00000000 02时50分30秒|
| * 无效 *| +00000000 03时02分50秒|
如果您想以不同的方式格式化它，可以将默认值INTERVAL DAY(9) TO SECOND(9)转换为精度更小的间隔，例如INTERVAL DAY(1) TO SECOND(0)：

SELECT video_id,                               
       CAST(
         SUM(
           EXTRACT(HOUR   FROM video_duration) * 60 * 60
         + EXTRACT(MINUTE FROM video_duration) * 60
         + EXTRACT(SECOND FROM video_duration)
         ) * INTERVAL '1' SECOND
         AS INTERVAL DAY(1) TO SECOND (0)
       ) AS total_duration
FROM   t_video
GROUP BY ROLLUP(video_id);

| 视频_ID|总计_持续时间|
| - ------| - ------|
| 1个|+0 00时12分20秒|
| 第二章|+0 02时50分30秒|
| * 无效 *| +0 03时02分50秒|
fiddle

最好的方法是将列的类型更改为interval day to second，然后就可以使用Oracle内置的时间间隔函数。

-- Make a new interval day to second column.
alter table t_video add video_duration_new interval day to second;

-- Translate your string durations into intervals.
-- to_dsinterval requires a day, so we add 0 days. This assumes all your video durations are all HH:MM:SS
update t_video set video_duration_new = to_dsinterval(concat('0 ', video_duration));

-- Drop the old column.
alter table t_video drop column video_duration;

-- Replace it with the interval column.
alter table t_video rename column video_duration_new to video_duration;

现在，使用extract获取小时数非常简单。

select extract(hour from video_duration) from t_video;

这也可以为性能编制索引，并将检查值的格式是否正确。
Demonstration.