SQL Server 2017

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CREATE TABLE #Monitoring(RowID int,DateStamp datetime2,Success bit,Error varchar(20))
INSERT INTO #Monitoring(RowID,DateStamp,Success,Error)
VALUES

 (1001        ,'5/24/2019 11:23am',    1              ,'None') 
,(1004        ,'5/24/2019 11:24am',    1              ,'bla') 
,(1005        ,'5/24/2019 11:25am',    1              ,'None') 
,(1009        ,'5/24/2019 11:26am',    0              ,'SQL Timeout')
,(1018        ,'5/24/2019 11:27am',    0              ,'SQL Timeout') 
,(1019        ,'5/24/2019 11:28am',    1              ,'None') 
,(1026        ,'5/24/2019 11:29am',    1              ,'None') 
,(1035        ,'5/24/2019 11:30am',    0              ,'Planned Maintenance')
,(1100        ,'5/24/2019 11:31am',    0              ,'Planned Maintenance')
,(1111        ,'5/24/2019 11:32am',    1              ,'None')
10 rows affected

;WITH CTE_GROUP AS (
  SELECT 
  Success, 
  Error,
  DateStamp,
  ROW_NUMBER() OVER (PARTITION BY Success ORDER BY DateStamp)
      - ROW_NUMBER() OVER (ORDER BY DateStamp) as SuccesDateStamp,
  ROW_NUMBER() OVER (PARTITION BY Error ORDER BY DateStamp)
      - ROW_NUMBER() OVER (ORDER BY DateStamp) as ErrorDateStamp
FROM #Monitoring
)
SELECT MIN(DateStamp) as Starting, MAX(DateStamp) as Ending, 
      Count(*) as Polls, Success, Error
FROM CTE_GROUP
GROUP BY Success, Error,SuccesDateStamp,ErrorDateStamp
ORDER BY Starting;


Starting
Ending
Polls
Success
Error


2019-05-24 11:23:00.0000000
2019-05-24 11:23:00.0000000
1
True
None

2019-05-24 11:24:00.0000000
2019-05-24 11:24:00.0000000
1
True
bla

2019-05-24 11:25:00.0000000
2019-05-24 11:25:00.0000000
1
True
None

2019-05-24 11:26:00.0000000
2019-05-24 11:27:00.0000000
2
False
SQL Timeout

2019-05-24 11:28:00.0000000
2019-05-24 11:29:00.0000000
2
True
None

2019-05-24 11:30:00.0000000
2019-05-24 11:31:00.0000000
2
False
Planned Maintenance

2019-05-24 11:32:00.0000000
2019-05-24 11:32:00.0000000
1
True
None


;WITH CTE_GROUP AS (
  SELECT 
  Success, 
  Error,
  DateStamp,
  ROW_NUMBER() OVER (PARTITION BY Success, Error ORDER BY DateStamp)
      - ROW_NUMBER() OVER (ORDER BY DateStamp) as SuccesErrorDateStamp
FROM #Monitoring
)
SELECT MIN(DateStamp) as Starting, MAX(DateStamp) as Ending, 
      Count(*) as Polls, Success, Error
FROM CTE_GROUP
GROUP BY Success, Error, SuccesErrorDateStamp
ORDER BY Starting;


Starting
Ending
Polls
Success
Error


2019-05-24 11:23:00.0000000
2019-05-24 11:23:00.0000000
1
True
None

2019-05-24 11:24:00.0000000
2019-05-24 11:24:00.0000000
1
True
bla

2019-05-24 11:25:00.0000000
2019-05-24 11:25:00.0000000
1
True
None

2019-05-24 11:26:00.0000000
2019-05-24 11:27:00.0000000
2
False
SQL Timeout

2019-05-24 11:28:00.0000000
2019-05-24 11:29:00.0000000
2
True
None

2019-05-24 11:30:00.0000000
2019-05-24 11:31:00.0000000
2
False
Planned Maintenance

2019-05-24 11:32:00.0000000
2019-05-24 11:32:00.0000000
1
True
None

Starting	Ending	Polls	Success	Error
2019-05-24 11:23:00.0000000	2019-05-24 11:23:00.0000000	1	True	None
2019-05-24 11:24:00.0000000	2019-05-24 11:24:00.0000000	1	True	bla
2019-05-24 11:25:00.0000000	2019-05-24 11:25:00.0000000	1	True	None
2019-05-24 11:26:00.0000000	2019-05-24 11:27:00.0000000	2	False	SQL Timeout
2019-05-24 11:28:00.0000000	2019-05-24 11:29:00.0000000	2	True	None
2019-05-24 11:30:00.0000000	2019-05-24 11:31:00.0000000	2	False	Planned Maintenance
2019-05-24 11:32:00.0000000	2019-05-24 11:32:00.0000000	1	True	None