MySQL 8.0

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CREATE TABLE mytable(
   id int auto_increment primary key
   ,startDate DATE  NOT NULL 
  ,endDate   DATE  NOT NULL
);
INSERT INTO mytable(startDate,endDate) VALUES ('2019-12-10','2019-12-15');
INSERT INTO mytable(startDate,endDate) VALUES ('2019-12-16','2019-12-22');
INSERT INTO mytable(startDate,endDate) VALUES ('2019-12-29','2019-01-05');
INSERT INTO mytable(startDate,endDate) VALUES ('2020-01-20','2020-01-25');
select * from mytable order by startDate


id
startDate
endDate


1
2019-12-10
2019-12-15

2
2019-12-16
2019-12-22

3
2019-12-29
2019-01-05

4
2020-01-20
2020-01-25


insert into mytable(startDate, endDate)
select i.startDate, i.endDate
from (select '2019-12-23' startDate, '2019-12-30' endDate) i
where not exists (
	select 1 
	from mytable t 
	where t.startDate <= i.endDate and t.endDate >= i.startDate
)
select * from mytable order by id


id
startDate
endDate


1
2019-12-10
2019-12-15

2
2019-12-16
2019-12-22

3
2019-12-29
2019-01-05

4
2020-01-20
2020-01-25

5
2019-12-23
2019-12-30


insert into mytable(startDate, endDate)
select i.startDate, i.endDate
from (select '2019-12-23' startDate, '2019-12-28' endDate) i
where not exists (
	select 1 
	from mytable t 
	where t.startDate <= i.endDate and t.endDate >= i.startDate
)
select * from mytable order by id


id
startDate
endDate


1
2019-12-10
2019-12-15

2
2019-12-16
2019-12-22

3
2019-12-29
2019-01-05

4
2020-01-20
2020-01-25

5
2019-12-23
2019-12-30

id	startDate	endDate
1	2019-12-10	2019-12-15
2	2019-12-16	2019-12-22
3	2019-12-29	2019-01-05
4	2020-01-20	2020-01-25