我编写了此SQL查询，该查询返回最近24小时每小时创建的记录数。该查询在第一天工作正常，但是从第二天开始，它将第一天的记录数与当前天数相加。
这是我当前的查询：
select h.hr, count(e.eventID) as cnt
from (
select 0 hr union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9 union all select 10 union all select 11 union all select 12 union all select 13 union all select 14 union all select 15 union all select 16 union all select 17 union all select 18 union all select 19 union all select 20 union all select 21 union all select 22 union all select 23
) h
left join events e
on e.timeStamp > now() - interval 24 hour
and hour(e.timeStamp) = h.hr
group by h.hr
我的数据集：
+---------+----------+---------------------+---------------------+
| eventID | personID | timeStamp | dateModified |
+---------+----------+---------------------+---------------------+
| 1 | 8 | 2019-12-28 12:26:49 | 2019-12-28 12:26:50 |
| 2 | 0 | 2019-12-28 12:26:51 | 2019-12-28 12:26:52 |
| 3 | 0 | 2019-12-28 12:27:11 | 2019-12-28 12:27:12 |
| 4 | 0 | 2019-12-28 12:27:12 | 2019-12-28 12:27:12 |
| 5 | 0 | 2019-12-28 12:28:20 | 2019-12-28 12:28:20 |
| 6 | 0 | 2019-12-28 12:28:21 | 2019-12-28 12:28:21 |
| 7 | 0 | 0000-00-00 00:00:00 | 2019-12-28 12:28:21 |
| 8 | 2 | 2019-12-28 12:30:02 | 2019-12-28 12:30:02 |
| 9 | 0 | 2019-12-28 12:30:03 | 2019-12-28 12:30:03 |
| 10 | 1 | 2019-12-30 05:38:02 | 2019-12-30 05:38:01 |
| 11 | 0 | 2019-12-30 05:38:05 | 2019-12-30 05:38:03 |
| 12 | 0 | 2019-12-30 05:41:42 | 2019-12-30 05:41:41 |
| 13 | 1 | 2019-12-30 05:41:41 | 2019-12-30 05:41:41 |
| 14 | 1 | 2019-12-30 05:43:11 | 2019-12-30 05:43:11 |
| 15 | 0 | 2019-12-30 05:43:13 | 2019-12-30 05:43:11 |
| 16 | 8 | 2019-12-30 05:44:08 | 2019-12-30 05:44:08 |
| 17 | 0 | 2019-12-30 05:44:10 | 2019-12-30 05:44:08 |
| 18 | 1 | 2019-12-30 05:48:06 | 2019-12-30 05:48:06 |
| 19 | 0 | 2019-12-30 05:48:08 | 2019-12-30 05:48:07 |
| 20 | 1 | 2019-12-30 06:09:58 | 2019-12-30 06:09:57 |
| 21 | 0 | 2019-12-30 06:10:00 | 2019-12-30 06:09:58 |
| 22 | 0 | 2019-12-30 06:11:22 | 2019-12-30 06:11:20 |
| 23 | 1 | 2019-12-30 06:11:20 | 2019-12-30 06:11:20 |
| 24 | 1 | 2019-12-30 06:13:30 | 2019-12-30 06:13:30 |
| 25 | 0 | 2019-12-30 06:13:32 | 2019-12-30 06:13:30 |
| 26 | 0 | 0000-00-00 00:00:00 | 2019-12-30 06:13:42 |
| 27 | 0 | 0000-00-00 00:00:00 | 2019-12-30 06:14:00 |
| 28 | 1 | 2019-12-30 06:14:55 | 2019-12-30 06:14:54 |
| 29 | 0 | 2019-12-30 06:14:57 | 2019-12-30 06:14:55 |
| 30 | 0 | 0000-00-00 00:00:00 | 2019-12-30 06:14:59 |
| 31 | 8 | 2019-12-30 06:16:22 | 2019-12-30 06:16:22 |
| 32 | 0 | 2019-12-30 06:16:24 | 2019-12-30 06:16:22 |
| 33 | 0 | 0000-00-00 00:00:00 | 2019-12-30 06:16:27 |
| 34 | 8 | 2019-12-30 06:17:56 | 2019-12-30 06:17:56 |
| 35 | 0 | 2019-12-30 06:17:58 | 2019-12-30 06:17:56 |
| 36 | 1 | 2019-12-30 06:18:32 | 2019-12-30 06:18:31 |
| 37 | 0 | 2019-12-30 06:18:33 | 2019-12-30 06:18:31 |
| 38 | 0 | 0000-00-00 00:00:00 | 2019-12-30 06:18:37 |
| 39 | 8 | 2019-12-30 06:21:23 | 2019-12-30 06:21:23 |
| 40 | 0 | 2019-12-30 06:21:25 | 2019-12-30 06:21:23 |
| 41 | 0 | 2019-12-30 06:21:33 | 2019-12-30 06:21:32 |
| 42 | 0 | 2019-12-30 06:21:34 | 2019-12-30 06:21:32 |
| 43 | 1 | 2019-12-30 06:39:58 | 2019-12-30 06:39:57 |
| 44 | 0 | 2019-12-30 06:40:00 | 2019-12-30 06:39:59 |
| 45 | 1 | 2019-12-30 06:40:29 | 2019-12-30 06:40:29 |
| 46 | 0 | 2019-12-30 06:40:31 | 2019-12-30 06:40:29 |
| 47 | 1 | 2019-12-30 06:42:06 | 2019-12-30 06:42:05 |
| 48 | 0 | 2019-12-30 06:42:07 | 2019-12-30 06:42:05 |
| 49 | 1 | 2019-12-30 06:44:21 | 2019-12-30 06:44:20 |
| 50 | 0 | 2019-12-30 06:44:22 | 2019-12-30 06:44:21 |
| 51 | 1 | 2019-12-30 06:45:35 | 2019-12-30 06:45:34 |
| 52 | 0 | 2019-12-30 06:45:36 | 2019-12-30 06:45:34 |
| 53 | 1 | 2019-12-30 06:46:27 | 2019-12-30 06:46:27 |
| 54 | 0 | 2019-12-30 06:46:28 | 2019-12-30 06:46:27 |
| 55 | 1 | 2019-12-30 06:50:40 | 2019-12-30 06:50:39 |
| 56 | 0 | 2019-12-30 06:50:41 | 2019-12-30 06:50:39 |
| 57 | 8 | 2019-12-30 08:10:52 | 2019-12-30 08:10:57 |
| 58 | 0 | 2019-12-30 08:10:59 | 2019-12-30 08:10:58 |
| 59 | 1 | 2019-12-30 09:47:06 | 2019-12-30 09:47:07 |
| 60 | 0 | 2019-12-30 09:47:08 | 2019-12-30 09:47:07 |
| 61 | 1 | 2019-12-30 11:43:17 | 2019-12-30 11:43:17 |
| 62 | 0 | 2019-12-30 11:43:18 | 2019-12-30 11:43:18 |
| 63 | 1 | 2019-12-30 11:43:35 | 2019-12-30 11:43:35 |
| 64 | 0 | 2019-12-30 11:43:36 | 2019-12-30 11:43:35 |
| 65 | 1 | 2019-12-30 11:44:05 | 2019-12-30 11:44:05 |
| 66 | 0 | 2019-12-30 11:44:06 | 2019-12-30 11:44:06 |
| 67 | 1 | 2019-12-30 12:26:47 | 2019-12-30 12:26:47 |
| 68 | 0 | 2019-12-30 12:26:49 | 2019-12-30 12:26:48 |
| 69 | 0 | 2019-12-30 12:40:34 | 2019-12-30 12:40:33 |
| 70 | 1 | 2019-12-30 12:40:33 | 2019-12-30 12:40:34 |
| 71 | 8 | 2019-12-31 04:52:29 | 2019-12-31 04:52:28 |
| 72 | 0 | 2019-12-31 04:52:31 | 2019-12-31 04:52:29 |
| 73 | 0 | 2019-12-31 04:53:50 | 2019-12-31 04:53:47 |
| 74 | 8 | 2019-12-31 04:53:48 | 2019-12-31 04:53:47 |
| 75 | 8 | 2019-12-31 04:54:14 | 2019-12-31 04:54:13 |
| 76 | 0 | 2019-12-31 04:54:16 | 2019-12-31 04:54:14 |
| 77 | 8 | 2019-12-31 04:54:40 | 2019-12-31 04:54:38 |
| 78 | 0 | 2019-12-31 04:54:41 | 2019-12-31 04:54:39 |
| 79 | 0 | 2019-12-31 04:55:11 | 2019-12-31 04:55:09 |
| 80 | 8 | 2019-12-31 04:55:10 | 2019-12-31 04:55:10 |
+---------+----------+---------------------+---------------------+
我要去哪里错了？
如果有人需要，这是我的timeStamp格式：2019-12-31 04:55:10
P.S：我的SQL不支持递归CTE，因此我不得不使用联合24次。
答案 0 :(得分：1)
我没有测试数据，但是这种冷就可以了：
select h.hr, count(e.eventID) as cnt
from (
select 0 hr union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9 union all select 10 union all select 11 union all select 12 union all select 13 union all select 14 union all select 15 union all select 16 union all select 17 union all select 18 union all select 19 union all select 20 union all select 21 union all select 22 union all select 23
) h
left join (select * from events e where e.timeStamp > now() - interval 24 hour) e
on hour(e.timeStamp) = h.hr
group by h.hr
IF
select * from events e where e.timeStamp > now() - interval 24 hour
仅提供最近24小时的记录
如果您想要过去一天的活动：
select h.hr, count(e.eventID) as cnt
from (
select 0 hr union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9 union all select 10 union all select 11 union all select 12 union all select 13 union all select 14 union all select 15 union all select 16 union all select 17 union all select 18 union all select 19 union all select 20 union all select 21 union all select 22 union all select 23
) h
left join (select * from events e where e.timeStamp > cast(now() as date)) e
on hour(e.timeStamp) = h.hr
group by h.hr