SQL Server 2019

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CREATE TABLE T (ID INT, FKID INT, Start DATETIME, [End] DATETIME, TotalTime DECIMAL(15, 10));

INSERT INTO T(ID, FKID, Start, [End], TotalTime)
VALUES
	(208, 40, '2021-07-29 09:30:00', '2021-07-29 09:30:00', 0.9),
	(209, 37, '2021-07-29 10:00:00', '2021-07-29 10:00:00', 0.9),
	(210, 39, '2021-07-29 10:15:00', '2021-07-29 11:32:00', 77.76),
	(211, 40, '2021-07-29 13:00:00', '2021-07-29 14:17:00', 77.76),
	(212, 34, '2021-07-29 13:00:00', '2021-07-29 14:28:00', 88.8685714285714),
	(213, 39, '2021-07-29 10:30:00', '2021-07-29 11:47:00', 77.76);
6 rows affected

SELECT	t1.*
FROM	T AS t1
		INNER JOIN T AS t2
			ON t2.FKID = t1.FKID -- SAME FKID
			AND t2.ID <> t1.ID -- Different ID
WHERE	(t2.Start > t1.Start AND t2.Start < t1.[End])
OR		(t2.[End] > t1.Start AND t2.[End] < t1.[End])


ID
FKID
Start
End
TotalTime


210
39
2021-07-29 10:15:00.000
2021-07-29 11:32:00.000
77.7600000000

213
39
2021-07-29 10:30:00.000
2021-07-29 11:47:00.000
77.7600000000


SELECT	t1.*
FROM	T AS t1
		INNER JOIN T AS t2
			ON t2.FKID = t1.FKID -- SAME FKID
			AND t2.ID <> t1.ID -- Different ID
WHERE	t2.Start < t1.[End]
AND		t2.[End] > t1.Start;


ID
FKID
Start
End
TotalTime


213
39
2021-07-29 10:30:00.000
2021-07-29 11:47:00.000
77.7600000000

210
39
2021-07-29 10:15:00.000
2021-07-29 11:32:00.000
77.7600000000

ID	FKID	Start	End	TotalTime
210	39	2021-07-29 10:15:00.000	2021-07-29 11:32:00.000	77.7600000000
213	39	2021-07-29 10:30:00.000	2021-07-29 11:47:00.000	77.7600000000