SQL Server 2019

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create table desks
(
start_date date,
stop_date date,
id varchar(10),
desk_number int
);

insert into desks values
('2020/01/20', 	'2020/05/20', 	'0100', 	55),
('2020/03/20', 	'2020/06/20', 	'0100', 	56),
('2020/02/22', 	'2020/04/22', 	'0200', 	91);
3 rows affected

create table teams
(
start_date date,
stop_date date,
id varchar(10),
team_number int
);

insert into teams values
('2020/01/20', 	'2020/04/20', 	'0100', 	2),
('2020/02/20', 	'2020/06/20', 	'0100', 	3),
('2020/02/22', 	'2020/04/22', 	'0200', 	8);
3 rows affected

SELECT CASE
         WHEN teams.start_date > desks.start_date
         THEN teams.start_date
         ELSE desks.start_date
       END start_date
     , CASE
         WHEN teams.stop_date < desks.stop_date
         THEN teams.stop_date
         ELSE desks.stop_date
      END stop_date
     , desks.id
     , desks.desk_number
     , teams.team_number
  FROM desks
  JOIN teams
    ON desks.start_date < teams.stop_date
   AND teams.start_date < desks.stop_date
   AND teams.id = desks.id
 ORDER BY desks.id, 1


start_date
stop_date
id
desk_number
team_number


2020-01-20
2020-04-20
0100
55
2

2020-02-20
2020-05-20
0100
55
3

2020-03-20
2020-06-20
0100
56
3

2020-03-20
2020-04-20
0100
56
2

2020-02-22
2020-04-22
0200
91
8

start_date	stop_date	id	desk_number	team_number
2020-01-20	2020-04-20	0100	55	2
2020-02-20	2020-05-20	0100	55	3
2020-03-20	2020-06-20	0100	56	3
2020-03-20	2020-04-20	0100	56	2
2020-02-22	2020-04-22	0200	91	8