我正在研究一个能源应用，我们正在监控工厂的柴油发电机和电表。
我们在数据库中有这些数据。以下是数据库中存在的一些记录。
ip meter_id device_time
===========================================
100.74.61.93 s1 r1 2018-11-01 09:02:42
100.74.61.93 s1 r1 2018-11-01 09:02:57
100.74.61.93 s1 r1 2018-11-01 09:03:12
100.74.61.93 s1 r1 2018-11-01 09:03:27
100.74.61.93 s1 r1 2018-11-01 09:03:42
100.74.61.93 s1 r1 2018-11-01 09:03:57
100.74.61.93 s1 r1 2018-11-01 09:04:17
100.74.61.93 s1 r1 2018-11-01 09:04:27
100.74.61.93 s1 r1 2018-11-01 09:04:47
100.74.61.93 s1 r1 2018-11-01 09:04:57
100.74.61.93 s1 r1 2018-11-01 09:05:12
100.74.61.93 s1 r1 2018-11-01 09:05:27
100.74.61.93 s1 r1 2018-11-01 09:05:47
100.74.61.93 s1 r1 2018-11-01 09:05:57
100.74.61.93 s1 r1 2018-11-01 09:06:12
100.74.61.93 s1 r1 2018-11-01 09:06:27
100.74.61.93 s1 r1 2018-11-01 09:06:42
100.74.61.93 s1 r1 2018-11-01 09:06:57
100.74.61.93 s1 r1 2018-11-01 09:07:12
100.74.61.93 s1 r1 2018-11-01 09:07:27
100.74.61.93 s1 r1 2018-11-01 09:07:42
100.74.61.93 s1 r1 2018-11-01 09:07:57
100.74.61.93 s1 r1 2018-11-01 09:08:12
100.74.61.93 s1 r1 2018-11-01 09:08:27
100.74.61.93 s1 r1 2018-11-01 09:08:47
100.74.61.93 s1 r1 2018-11-01 09:08:57
100.74.61.93 s1 r1 2018-11-01 09:09:12
100.74.61.93 s1 r1 2018-11-01 09:09:27
100.74.61.93 s1 r1 2018-11-01 09:09:42
100.74.61.93 s1 r1 2018-11-01 09:09:57
100.74.61.93 s1 r1 2018-11-01 09:10:12
100.74.61.93 s1 r1 2018-11-01 09:10:27
100.74.61.93 s1 r1 2018-11-01 09:10:42
100.74.61.93 s1 r1 2018-11-01 09:10:57
100.74.61.93 s1 r1 2018-11-01 09:11:12
100.74.61.93 s1 r1 2018-11-01 09:11:27
100.74.61.93 s1 r1 2018-11-01 09:11:42
100.74.61.93 s1 r1 2018-11-01 09:11:57
100.74.61.93 s1 r1 2018-11-01 09:12:12
100.74.61.93 s1 r1 2018-11-01 09:12:27
100.74.61.93 s1 r1 2018-11-01 09:12:42
100.74.61.93 s1 r1 2018-11-01 09:12:57
100.74.61.93 s1 r1 2018-11-01 09:13:12
100.74.61.93 s1 r1 2018-11-01 09:13:27
100.74.61.93 s1 r1 2018-11-01 11:15:42
100.74.61.93 s1 r1 2018-11-01 09:13:42
100.74.61.93 s1 r1 2018-11-01 09:13:57
100.74.61.93 s1 r1 2018-11-01 11:15:58
100.74.61.93 s1 r1 2018-11-01 11:16:12
100.74.61.93 s1 r1 2018-11-01 11:13:42
100.74.61.93 s1 r1 2018-11-01 11:13:57
100.74.61.93 s1 r1 2018-11-01 11:14:12
100.74.61.93 s1 r1 2018-11-01 11:14:27
100.74.61.93 s1 r1 2018-11-01 11:14:42
100.74.61.93 s1 r1 2018-11-01 11:14:57
100.74.61.93 s1 r1 2018-11-01 11:15:12
100.74.61.93 s1 r1 2018-11-01 11:15:27
100.74.61.93 s1 r1 2018-11-01 11:16:27
100.74.61.93 s1 r1 2018-11-01 11:16:42
100.74.61.93 s1 r1 2018-11-01 11:16:57
100.74.61.93 s1 r1 2018-11-01 11:17:13
100.74.61.93 s1 r1 2018-11-01 11:17:27
100.74.61.93 s1 r1 2018-11-01 11:17:42
100.74.61.93 s1 r1 2018-11-01 11:17:57
100.74.61.93 s1 r1 2018-11-01 11:18:12
100.74.61.93 s1 r1 2018-11-01 11:18:28
100.74.61.93 s1 r1 2018-11-01 11:18:42
100.74.61.93 s1 r1 2018-11-01 11:18:58
100.74.61.93 s1 r1 2018-11-01 11:19:12
100.74.61.93 s1 r1 2018-11-01 11:19:27
100.74.61.93 s1 r1 2018-11-01 11:19:42
100.74.61.93 s1 r1 2018-11-01 11:19:58
100.74.61.93 s1 r1 2018-11-01 11:20:13
100.74.61.93 s1 r1 2018-11-01 11:20:27
100.74.61.93 s1 r1 2018-11-01 11:20:43
100.74.61.93 s1 r1 2018-11-01 11:20:58
100.74.61.93 s1 r1 2018-11-01 11:21:13
100.74.61.93 s1 r1 2018-11-01 11:21:28
100.74.61.93 s1 r1 2018-11-01 11:21:43
100.74.61.93 s1 r1 2018-11-01 11:21:58
100.74.61.93 s1 r1 2018-11-01 11:48:58
100.74.61.93 s1 r1 2018-11-01 11:49:13
100.74.61.93 s1 r1 2018-11-01 11:49:28
100.74.61.93 s1 r1 2018-11-01 11:49:43
100.74.61.93 s1 r1 2018-11-01 11:49:58
100.74.61.93 s1 r1 2018-11-01 11:50:13
100.74.61.93 s1 r1 2018-11-01 11:50:28
100.74.61.93 s1 r1 2018-11-01 11:50:43
100.74.61.93 s1 r1 2018-11-01 11:50:58
100.74.61.93 s1 r1 2018-11-01 11:51:13
100.74.61.93 s1 r1 2018-11-01 11:51:28
100.74.61.93 s1 r1 2018-11-01 11:51:43
100.74.61.93 s1 r1 2018-11-01 11:51:58
100.74.61.93 s1 r1 2018-11-01 11:52:13
100.74.61.93 s1 r1 2018-11-01 11:52:28
100.74.61.93 s1 r1 2018-11-01 11:52:43
100.74.61.93 s1 r1 2018-11-01 11:52:58
100.74.61.93 s1 r1 2018-11-01 11:53:13
100.74.61.93 s1 r1 2018-11-01 11:53:28
100.74.61.93 s1 r1 2018-11-01 11:53:43
100.74.61.93 s1 r1 2018-11-01 11:53:58
100.74.61.93 s1 r1 2018-11-01 11:54:13
100.74.61.93 s1 r1 2018-11-01 11:54:28
100.74.61.93 s1 r1 2018-11-01 11:54:43
100.74.61.93 s1 r1 2018-11-01 11:54:58
100.74.61.93 s1 r1 2018-11-01 11:55:13
100.74.61.93 s1 r1 2018-11-01 11:55:28
100.74.61.93 s1 r1 2018-11-01 11:55:43
100.74.61.93 s1 r1 2018-11-01 11:55:58
100.74.61.93 s1 r1 2018-11-01 11:56:13
100.74.61.93 s1 r1 2018-11-01 11:56:28
正如您可以从数据库中检查上述记录，每一行都具有device_time这意味着当时柴油发电机正在运行。
现在我想以这样的格式计算时间，01 days, 2 hours, 10 min它会告诉我它运行了多少总时间？
我写了给我结果的查询。
select
count(device_timestamp) * '1 minute'::interval as operatingtime
from
(
select
time_bucket('1 min',
device_time at time zone 'Asia/Kolkata') as device_timestamp
from
public.schneider_new
where
meter_id in ('s1')
and device_time >= '2018-11-01T00:00:00.000'
and device_time <= now()
group by
device_timestamp
order by
device_timestamp as ) as tab
输出：
0 年 0 月 0 天 30 小时 28 分钟 0.00 秒
这给了我结果，但我不想0 years 0 mons 0 secs在上面的输出中。
而且，如果小时数大于 24 小时，即在这种情况下为 30 小时，则结果应为1 day 6 hours 28 mins。
我哪里错了？或者有没有其他方法可以计算 DG 在给定时间段内运行的时间？
更新：
我用这个尝试了查询
(count(device_timestamp)::numeric/60)/24 * '1 day'::interval as operatingtime
输出：
0 年 0 月 1 天 6 小时 28 分钟 0.00 秒
我得到了正确的输出，即1 days 6 hours 28 mins，我现在唯一要寻找的是删除另一个0 years 0 mons 0.00 secs。