MySQL 8.0

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select version();


version()


8.0.27


CREATE TABLE record (
    eventDate date,
    event VARCHAR(100),
    eventStart TIMESTAMP,
    eventEnd TIMESTAMP,
    durations double
);

INSERT INTO record VALUES 
( '2020-02-01' , 'eventB', '2020-02-01 09:10:25', '2020-02-01 09:50:25', 40.0 ),
( '2020-02-01' , 'eventD', '2020-02-01 09:15:25', '2020-02-01 09:20:25', 5.0),
( '2020-02-01' , 'eventC', '2020-02-01 09:30:25', '2020-02-01 09:35:25', 5.0),
( '2020-02-01' , 'eventD', '2020-02-01 09:40:25', '2020-02-01 09:45:25', 5.0),
( '2020-02-01' , 'eventC', '2020-02-01 09:55:25', '2020-02-01 09:59:25', 4.0);
delete from record;
INSERT INTO record VALUES 
( '2020-02-01' , 'eventB', '2020-02-01 09:10:25', '2020-02-01 09:50:25', 40.0 ),
( '2020-02-01' , 'eventD', '2020-02-01 09:15:25', '2020-02-01 09:20:25', 5.0),
( '2020-02-01' , 'eventC', '2020-02-01 09:30:25', '2020-02-01 09:35:25', 5.0),
( '2020-02-01' , 'eventD', '2020-02-01 09:40:25', '2020-02-01 09:45:25', 5.0),
( '2020-02-01' , 'eventC', '2020-02-01 09:55:25', '2020-02-01 09:59:25', 4.0);
select r1.*, r2.event "OverlapsWith"
from record r1
inner join record r2 on r1.eventStart <= r2.eventEnd
                     and r1.eventEnd >= r2.eventStart 


eventDate
event
eventStart
eventEnd
durations
OverlapsWith


2020-02-01
eventD
2020-02-01 09:40:25
2020-02-01 09:45:25
5
eventB

2020-02-01
eventC
2020-02-01 09:30:25
2020-02-01 09:35:25
5
eventB

2020-02-01
eventD
2020-02-01 09:15:25
2020-02-01 09:20:25
5
eventB

2020-02-01
eventB
2020-02-01 09:10:25
2020-02-01 09:50:25
40
eventB

2020-02-01
eventD
2020-02-01 09:15:25
2020-02-01 09:20:25
5
eventD

2020-02-01
eventB
2020-02-01 09:10:25
2020-02-01 09:50:25
40
eventD

2020-02-01
eventC
2020-02-01 09:30:25
2020-02-01 09:35:25
5
eventC

2020-02-01
eventB
2020-02-01 09:10:25
2020-02-01 09:50:25
40
eventC

2020-02-01
eventD
2020-02-01 09:40:25
2020-02-01 09:45:25
5
eventD

2020-02-01
eventB
2020-02-01 09:10:25
2020-02-01 09:50:25
40
eventD

2020-02-01
eventC
2020-02-01 09:55:25
2020-02-01 09:59:25
4
eventC


select * from record;


eventDate
event
eventStart
eventEnd
durations


2020-02-01
eventB
2020-02-01 09:10:25
2020-02-01 09:50:25
40

2020-02-01
eventD
2020-02-01 09:15:25
2020-02-01 09:20:25
5

2020-02-01
eventC
2020-02-01 09:30:25
2020-02-01 09:35:25
5

2020-02-01
eventD
2020-02-01 09:40:25
2020-02-01 09:45:25
5

2020-02-01
eventC
2020-02-01 09:55:25
2020-02-01 09:59:25
4

eventDate	event	eventStart	eventEnd	durations	OverlapsWith
2020-02-01	eventD	2020-02-01 09:40:25	2020-02-01 09:45:25	5	eventB
2020-02-01	eventC	2020-02-01 09:30:25	2020-02-01 09:35:25	5	eventB
2020-02-01	eventD	2020-02-01 09:15:25	2020-02-01 09:20:25	5	eventB
2020-02-01	eventB	2020-02-01 09:10:25	2020-02-01 09:50:25	40	eventB
2020-02-01	eventD	2020-02-01 09:15:25	2020-02-01 09:20:25	5	eventD
2020-02-01	eventB	2020-02-01 09:10:25	2020-02-01 09:50:25	40	eventD
2020-02-01	eventC	2020-02-01 09:30:25	2020-02-01 09:35:25	5	eventC
2020-02-01	eventB	2020-02-01 09:10:25	2020-02-01 09:50:25	40	eventC
2020-02-01	eventD	2020-02-01 09:40:25	2020-02-01 09:45:25	5	eventD
2020-02-01	eventB	2020-02-01 09:10:25	2020-02-01 09:50:25	40	eventD
2020-02-01	eventC	2020-02-01 09:55:25	2020-02-01 09:59:25	4	eventC