如何解决当两个或多个连续的行具有相同的状态时如何选择一行
说明： 我有一个表，该表维护带有日期时间的传感器及其状态（运行/已停止）数据。如下图所示：
我将此数据转换为：
使用此查询：
select * from (
Select A.TagName,(select top 1 EventTime from PumpRunCounts_perf where status = 'Running' and EventTime<A.EventTime order by 1 desc) StartTime,A.EventTime,A.Statuses
from (select * from PumpRunCounts_perf where status = 'Stopped')A
)A
但是，如果存在连续状态，就会出现问题，如下所示
我想要在连续状态下实现的是，当给出连续的“运行”状态时，选择最旧的一个，而当连续的“停止”状态时选择最新的。
赞：
我已经使用游标完成了工作，但是超过50万行需要花费数天才能完成。为了简单起见，不共享游标代码，请根据需要告知我。
请帮助我完成此任务。谢谢
请参阅示例表架构和数据
CREATE TABLE [dbo].[pumpruncounts_pref](
[ID] [nvarchar](36) NULL,[EventTime] [datetime2](7) NULL,[Tagname] [nvarchar](4000) NULL,[Status] [nvarchar](4000) NULL
) ON [PRIMARY]
GO
INSERT [dbo].[pumpruncounts_pref] ([ID],[EventTime],[Tagname],[Status]) VALUES (N'C6A41E1E-2C5B-4A7A-8858-67EBA622DC24',CAST(N'2020-07-22T23:06:00.0700000' AS DateTime2),N'PS44_P06.RunS',N'Stopped')
GO
INSERT [dbo].[pumpruncounts_pref] ([ID],[Status]) VALUES (N'EDDE7B77-4A59-4BE0-95F5-31532BF2CBA1',CAST(N'2020-07-21T12:06:45.5640000' AS DateTime2),N'Running')
GO
INSERT [dbo].[pumpruncounts_pref] ([ID],[Status]) VALUES (N'B44CAC7C-B648-44BD-9BC1-B647CE448124',CAST(N'2020-07-23T19:10:50.3870000' AS DateTime2),[Status]) VALUES (N'093C6C46-2A38-4A71-83B2-FDF849B06016',CAST(N'2020-07-18T05:54:52.7430000' AS DateTime2),[Status]) VALUES (N'69A1610E-6859-4C56-845C-0A4EFF215A41',CAST(N'2020-07-20T04:59:45.2150000' AS DateTime2),[Status]) VALUES (N'37DD901A-F2A0-4142-887D-D22CB38BB1F2',CAST(N'2020-07-20T03:19:40.7580000' AS DateTime2),[Status]) VALUES (N'1D3F54F6-A129-43BB-B30B-4782AB587711',CAST(N'2020-07-24T03:39:44.4840000' AS DateTime2),[Status]) VALUES (N'8A9C9058-4721-4C4F-A0D4-0B93B48AEC1A',CAST(N'2020-07-22T01:57:20.8030000' AS DateTime2),[Status]) VALUES (N'A41E1295-C196-4E24-BDF4-62FC0B321BE3',CAST(N'2020-07-23T10:36:46.2140000' AS DateTime2),[Status]) VALUES (N'7EAB2F61-EC61-448B-AA41-5C097C2F01EE',CAST(N'2020-07-20T13:41:35.4600000' AS DateTime2),[Status]) VALUES (N'75746488-03B4-4639-B1AD-9882297B8FA6',CAST(N'2020-07-23T20:01:12.6110000' AS DateTime2),[Status]) VALUES (N'3ADA8A20-0E79-4AAA-A7A7-FC17C7FC21E4',CAST(N'2020-07-19T04:12:21.9360000' AS DateTime2),[Status]) VALUES (N'4CCEF052-46B1-4674-8278-C6649FD42C85',CAST(N'2020-07-23T10:10:33.3180000' AS DateTime2),[Status]) VALUES (N'707EB5F2-CF3B-4699-9C59-C883615897C5',CAST(N'2020-07-21T21:54:10.1870000' AS DateTime2),[Status]) VALUES (N'E7104F6D-82E3-49F5-B446-6A371A1E558A',CAST(N'2020-07-21T21:05:57.5550000' AS DateTime2),[Status]) VALUES (N'23358E48-E947-4273-ACCC-E52A0A8DB137',CAST(N'2020-07-22T16:33:22.3440000' AS DateTime2),[Status]) VALUES (N'274C023F-5E7B-4626-AD96-CA9BB42EE6A0',CAST(N'2020-07-22T03:34:21.3950000' AS DateTime2),[Status]) VALUES (N'C58C6FB7-478E-4E32-AB08-535218AC3306',CAST(N'2020-07-24T04:12:08.0600000' AS DateTime2),[Status]) VALUES (N'3F4E8D3C-0101-4A74-93CC-922F7700C83B',CAST(N'2020-07-20T19:04:40.4240000' AS DateTime2),[Status]) VALUES (N'A1C363E2-3F14-4F9A-80B8-DC8B6634C2AB',CAST(N'2020-07-20T22:20:48.7130000' AS DateTime2),[Status]) VALUES (N'95DC2DD7-CD27-4783-864D-4287A90DEDB3',CAST(N'2020-07-19T21:27:06.5570000' AS DateTime2),[Status]) VALUES (N'9D3BAA7D-569D-414C-ADE0-F5263BACE1FF',CAST(N'2020-07-20T16:39:15.2270000' AS DateTime2),[Status]) VALUES (N'B1C3AE46-3713-40A9-BA46-C3209EB7120C',CAST(N'2020-07-24T04:40:33.3250000' AS DateTime2),[Status]) VALUES (N'DC1F0A0A-D767-494F-968A-07B6823CB26D',CAST(N'2020-07-20T20:14:50.2330000' AS DateTime2),[Status]) VALUES (N'B497FA37-0E0F-4C19-9DF3-16735799ED02',CAST(N'2020-07-19T14:25:49.0880000' AS DateTime2),[Status]) VALUES (N'CAAED751-4EE5-4FEF-98E2-0EEE8243CC1C',CAST(N'2020-07-22T04:06:56.9780000' AS DateTime2),[Status]) VALUES (N'46258565-5C3F-45FB-AA36-78E3AAE0E88B',CAST(N'2020-07-23T03:43:54.3460000' AS DateTime2),[Status]) VALUES (N'F7A1DB90-11D0-489F-A7BF-3D882153C6F3',CAST(N'2020-07-21T04:13:58.3370000' AS DateTime2),[Status]) VALUES (N'38496DC3-BC8D-4D4C-9F0F-A0FC6285C009',CAST(N'2020-07-24T04:06:56.3970000' AS DateTime2),[Status]) VALUES (N'3FE2CA7D-D059-403C-8BF2-9E2167B2D758',CAST(N'2020-07-23T17:26:22.8540000' AS DateTime2),[Status]) VALUES (N'EB1591B1-73D8-4755-9B4C-0222ADA4BA2D',CAST(N'2020-07-18T05:59:27.6120000' AS DateTime2),[Status]) VALUES (N'44743BDB-E084-4B5F-86A0-99812EC1452D',CAST(N'2020-07-19T04:08:14.9520000' AS DateTime2),[Status]) VALUES (N'C9AC6855-1BDF-4B5C-9514-1CAE0D86E1D0',CAST(N'2020-07-22T20:51:39.3850000' AS DateTime2),[Status]) VALUES (N'7E65B1CD-EE80-48C7-8DFD-F5A0F8C1D4E5',CAST(N'2020-07-18T16:44:55.2720000' AS DateTime2),[Status]) VALUES (N'0CAFDFDF-CA04-4B8E-81FD-E54C96338120',CAST(N'2020-07-23T02:42:17.7990000' AS DateTime2),[Status]) VALUES (N'DE7EA0C5-2EB9-4433-B99D-253711F0D990',CAST(N'2020-07-22T03:29:24.8290000' AS DateTime2),[Status]) VALUES (N'DB459A4A-F03E-4911-9134-AB74C5763A29',CAST(N'2020-07-19T15:59:08.0170000' AS DateTime2),[Status]) VALUES (N'C0AAABE7-D3C8-4E58-8501-44F2807992F0',CAST(N'2020-07-21T03:37:42.8400000' AS DateTime2),[Status]) VALUES (N'F9E84C95-D1B8-42BE-8E51-A1E5BC63823C',CAST(N'2020-07-22T02:22:35.4930000' AS DateTime2),[Status]) VALUES (N'3C12D9B6-38FC-4CD0-B668-EC583D072DC0',CAST(N'2020-07-21T02:30:25.0890000' AS DateTime2),[Status]) VALUES (N'D8B005DF-3443-49BD-ACFD-803CFDDEF58D',CAST(N'2020-07-21T04:47:35.6360000' AS DateTime2),[Status]) VALUES (N'3D6D5222-9B25-45C1-A73A-2E31F9DED4E3',CAST(N'2020-07-23T15:16:24.2680000' AS DateTime2),[Status]) VALUES (N'F9EC2A51-0F1F-4BCB-8FAE-DE70B89BB590',CAST(N'2020-07-23T16:56:09.4620000' AS DateTime2),[Status]) VALUES (N'433A4288-2FE3-4C7B-9205-16E98D1A376B',CAST(N'2020-07-19T14:47:55.5760000' AS DateTime2),[Status]) VALUES (N'D05ED43A-244F-43B5-B778-38442CF2F6A4',CAST(N'2020-07-22T23:06:41.4140000' AS DateTime2),[Status]) VALUES (N'D1399731-0F0F-4019-A8A5-12A7E2CD9D36',CAST(N'2020-07-21T04:18:24.7070000' AS DateTime2),[Status]) VALUES (N'B8231929-2062-45A4-A7E6-939EF4E994F2',CAST(N'2020-07-20T04:29:50.5050000' AS DateTime2),[Status]) VALUES (N'5D88B78F-6178-4B4E-8ACA-FD888E916DB5',CAST(N'2020-07-22T10:33:41.0020000' AS DateTime2),[Status]) VALUES (N'4FB517BD-401C-451A-AE35-EEF80D5262AE',CAST(N'2020-07-22T04:01:47.3900000' AS DateTime2),[Status]) VALUES (N'3E673EB3-BC3D-40B7-9BDA-ABDF192CE012',CAST(N'2020-07-22T20:28:47.4780000' AS DateTime2),N'Stopped')
GO
解决方法
对于我来说，您想要以后停止行而不是第一行对我来说似乎很奇怪。但这就是您在这里提出的问题。
一种方法使用lag()和lead()仅在停止（或NULL）和“停顿”的行之后保留“正在运行”的行，而下一行是“正在运行”（或NULL）。
然后，一个简单的lead()过滤器就会得到您想要的内容：
select tagname,eventtime as starttime,next_eventtime as endtime
from (select p.*,lead(eventtime) over (partition by tagname order by eventtime) as next_eventtime
from (select p.*,lag(status) over (partition by tagname order by eventtime) as prev_status,lead(status) over (partition by tagname order by eventtime) as next_status
from pumpruncounts_pref p
) p
where ( status = 'Running' and (prev_status is null or prev_status = 'Stopped') ) or
( status = 'Stopped' and (next_status is null or next_status = 'Running') )
) p
where status = 'Running';
Here是db 小提琴。
如果您实际上希望先先停靠（这对我来说更有意义），那么您可以调整停靠点的逻辑以模仿起跑点（即查看前一行而不是看前一行）下一个）。
为提高性能，请在(tagname,eventtime,status)上添加索引。
或者使用开始和停止，其前任和后继来确定开始，运行和结束；然后在每次遇到“真实”开始时添加一个总和1，使用该总和作为会话标识符，最后按标记名和会话ID分组。
您在WITH关键字之后的公共表表达式中输入的内容，
然后是两个后续CTE（显示中间结果），最后是GROUP BY查询。
WITH
pumpruncounts_pref(id,tagname,status) AS (
SELECT 'C9AC6855-1BDF-4B5C-9514-1CAE0D86E1D0',TIMESTAMP '2020-07-22T20:51:39.3850000','PS44_P06.RunS','Running'
UNION ALL SELECT '7E65B1CD-EE80-48C7-8DFD-F5A0F8C1D4E5',TIMESTAMP '2020-07-18T16:44:55.2720000','Stopped'
UNION ALL SELECT '0CAFDFDF-CA04-4B8E-81FD-E54C96338120',TIMESTAMP '2020-07-23T02:42:17.7990000','Stopped'
UNION ALL SELECT 'DE7EA0C5-2EB9-4433-B99D-253711F0D990',TIMESTAMP '2020-07-22T03:29:24.8290000','Running'
UNION ALL SELECT 'DB459A4A-F03E-4911-9134-AB74C5763A29',TIMESTAMP '2020-07-19T15:59:08.0170000','Running'
UNION ALL SELECT 'C0AAABE7-D3C8-4E58-8501-44F2807992F0',TIMESTAMP '2020-07-21T03:37:42.8400000','Running'
UNION ALL SELECT 'F9E84C95-D1B8-42BE-8E51-A1E5BC63823C',TIMESTAMP '2020-07-22T02:22:35.4930000','Running'
UNION ALL SELECT '3C12D9B6-38FC-4CD0-B668-EC583D072DC0',TIMESTAMP '2020-07-21T02:30:25.0890000','Running'
UNION ALL SELECT 'D8B005DF-3443-49BD-ACFD-803CFDDEF58D',TIMESTAMP '2020-07-21T04:47:35.6360000','Running'
UNION ALL SELECT '3D6D5222-9B25-45C1-A73A-2E31F9DED4E3',TIMESTAMP '2020-07-23T15:16:24.2680000','Stopped'
UNION ALL SELECT 'F9EC2A51-0F1F-4BCB-8FAE-DE70B89BB590',TIMESTAMP '2020-07-23T16:56:09.4620000','Stopped'
UNION ALL SELECT '433A4288-2FE3-4C7B-9205-16E98D1A376B',TIMESTAMP '2020-07-19T14:47:55.5760000','Running'
UNION ALL SELECT 'D05ED43A-244F-43B5-B778-38442CF2F6A4',TIMESTAMP '2020-07-22T23:06:41.4140000','Stopped'
UNION ALL SELECT 'D1399731-0F0F-4019-A8A5-12A7E2CD9D36',TIMESTAMP '2020-07-21T04:18:24.7070000','Stopped'
UNION ALL SELECT 'B8231929-2062-45A4-A7E6-939EF4E994F2',TIMESTAMP '2020-07-20T04:29:50.5050000','Stopped'
UNION ALL SELECT '5D88B78F-6178-4B4E-8ACA-FD888E916DB5',TIMESTAMP '2020-07-22T10:33:41.0020000','Running'
UNION ALL SELECT '4FB517BD-401C-451A-AE35-EEF80D5262AE',TIMESTAMP '2020-07-22T04:01:47.3900000','Running'
UNION ALL SELECT '3E673EB3-BC3D-40B7-9BDA-ABDF192CE012',TIMESTAMP '2020-07-22T20:28:47.4780000','Stopped'
),with_chg AS (
SELECT
eventtime,status,CASE
WHEN ISNULL(LAG(status) OVER(PARTITION BY tagname ORDER BY eventtime),'Stopped')='Stopped'
AND status='Running'
THEN 'Start'
WHEN ISNULL(LEAD(status) OVER(PARTITION BY tagname ORDER BY eventtime),'Running')='Running'
AND status='Stopped'
THEN 'Stop'
ELSE 'Running'
END AS newstat
FROM pumpruncounts_pref
)
-- out eventtime | tagname | status | newstat
-- out -------------------------+---------------+---------+---------
-- out 2020-07-18 16:44:55.272 | PS44_P06.RunS | Stopped | Stop
-- out 2020-07-19 14:47:55.576 | PS44_P06.RunS | Running | Start
-- out 2020-07-19 15:59:08.017 | PS44_P06.RunS | Running | Running
-- out 2020-07-20 04:29:50.505 | PS44_P06.RunS | Stopped | Stop
-- out 2020-07-21 02:30:25.089 | PS44_P06.RunS | Running | Start
-- out 2020-07-21 03:37:42.84 | PS44_P06.RunS | Running | Running
-- out 2020-07-21 04:18:24.707 | PS44_P06.RunS | Stopped | Stop
-- out 2020-07-21 04:47:35.636 | PS44_P06.RunS | Running | Start
-- out 2020-07-22 02:22:35.493 | PS44_P06.RunS | Running | Running
-- out 2020-07-22 03:29:24.829 | PS44_P06.RunS | Running | Running
-- out 2020-07-22 04:01:47.39 | PS44_P06.RunS | Running | Running
-- out 2020-07-22 10:33:41.002 | PS44_P06.RunS | Running | Running
-- out 2020-07-22 20:28:47.478 | PS44_P06.RunS | Stopped | Stop
-- out 2020-07-22 20:51:39.385 | PS44_P06.RunS | Running | Start
-- out 2020-07-22 23:06:41.414 | PS44_P06.RunS | Stopped | Running
-- out 2020-07-23 02:42:17.799 | PS44_P06.RunS | Stopped | Running
-- out 2020-07-23 15:16:24.268 | PS44_P06.RunS | Stopped | Running
-- out 2020-07-23 16:56:09.462 | PS44_P06.RunS | Stopped | Stop
-- out (18 rows)
-- out
-- out Time: First fetch (18 rows): 24.252 ms. All rows formatted: 24.307 ms,with_session AS (
SELECT
eventtime,newstat,SUM(
CASE newstat
WHEN 'Start' THEN 1
ELSE 0
END
) OVER (PARTITION BY tagname ORDER BY eventtime) AS session_id
FROM with_chg
)
-- out eventtime | tagname | status | newstat | session_id
-- out -------------------------+---------------+---------+---------+------------
-- out 2020-07-18 16:44:55.272 | PS44_P06.RunS | Stopped | Stop | 0
-- out 2020-07-19 14:47:55.576 | PS44_P06.RunS | Running | Start | 1
-- out 2020-07-19 15:59:08.017 | PS44_P06.RunS | Running | Running | 1
-- out 2020-07-20 04:29:50.505 | PS44_P06.RunS | Stopped | Stop | 1
-- out 2020-07-21 02:30:25.089 | PS44_P06.RunS | Running | Start | 2
-- out 2020-07-21 03:37:42.84 | PS44_P06.RunS | Running | Running | 2
-- out 2020-07-21 04:18:24.707 | PS44_P06.RunS | Stopped | Stop | 2
-- out 2020-07-21 04:47:35.636 | PS44_P06.RunS | Running | Start | 3
-- out 2020-07-22 02:22:35.493 | PS44_P06.RunS | Running | Running | 3
-- out 2020-07-22 03:29:24.829 | PS44_P06.RunS | Running | Running | 3
-- out 2020-07-22 04:01:47.39 | PS44_P06.RunS | Running | Running | 3
-- out 2020-07-22 10:33:41.002 | PS44_P06.RunS | Running | Running | 3
-- out 2020-07-22 20:28:47.478 | PS44_P06.RunS | Stopped | Stop | 3
-- out 2020-07-22 20:51:39.385 | PS44_P06.RunS | Running | Start | 4
-- out 2020-07-22 23:06:41.414 | PS44_P06.RunS | Stopped | Running | 4
-- out 2020-07-23 02:42:17.799 | PS44_P06.RunS | Stopped | Running | 4
-- out 2020-07-23 15:16:24.268 | PS44_P06.RunS | Stopped | Running | 4
-- out 2020-07-23 16:56:09.462 | PS44_P06.RunS | Stopped | Stop | 4
SELECT
tagname,session_id,MIN(eventtime) AS start_ts,MAX(eventtime) AS end_ts
FROM with_session
GROUP BY
tagname,session_id
ORDER BY
tagname,session_id
-- out tagname | session_id | start_ts | end_ts
-- out ---------------+------------+-------------------------+-------------------------
-- out PS44_P06.RunS | 0 | 2020-07-18 16:44:55.272 | 2020-07-18 16:44:55.272
-- out PS44_P06.RunS | 1 | 2020-07-19 14:47:55.576 | 2020-07-20 04:29:50.505
-- out PS44_P06.RunS | 2 | 2020-07-21 02:30:25.089 | 2020-07-21 04:18:24.707
-- out PS44_P06.RunS | 3 | 2020-07-21 04:47:35.636 | 2020-07-22 20:28:47.478
-- out PS44_P06.RunS | 4 | 2020-07-22 20:51:39.385 | 2020-07-23 16:56:09.462
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