SQL Server 2019

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create table #T (ID1 INT, ID2 INT, StartDate DATE, EndDate DATE)

insert into #T values
(100, 764286, '2019-05-01', '2019-05-31'),
(100, 764287, '2019-06-01', '2019-06-30'),
(100, 764288, '2019-07-10', '2019-07-31'),
(101, 764289, '2020-02-01', '2020-02-29'),
(101, 764290, '2020-02-29', '2020-03-31'),
(102, 764291, '2021-10-01', '2021-10-31'),
(102, 764292, '2021-11-01', '2021-11-30'),
(102, 764293, '2021-11-30', '2021-12-31'),
(103, 764294, '2022-01-01', '2022-01-31');
9 rows affected

select id1, max(id2) as id2, min(startdate) as startdate, max(enddate) as enddate
from
(
  select *, sum(addone) over(partition by id1 order by startdate,enddate,id2 rows unbounded preceding) as grp
  from
  ( 
    select *, 
      case when startdate <= dateadd(day, 1, max(enddate) over(partition by id1 order by startdate,enddate,id2 rows between unbounded preceding and 1 preceding))
           then 0 
           else 1 
      end as addone
    from #T
   ) as r
) as g
group by id1, grp
order by id1, startdate ;


id1
id2
startdate
enddate


100
764287
2019-05-01
2019-06-30

100
764288
2019-07-10
2019-07-31

101
764290
2020-02-01
2020-03-31

102
764293
2021-10-01
2021-12-31

103
764294
2022-01-01
2022-01-31


select @@version;


(No column name)


Microsoft SQL Server 2019 (RTM-CU16) (KB5011644) - 15.0.4223.1 (X64) 
	Apr 11 2022 16:24:07 
	Copyright (C) 2019 Microsoft Corporation
	Express Edition (64-bit) on Windows Server 2019 Standard 10.0 <X64> (Build 17763: ) (Hypervisor)

id1	id2	startdate	enddate
100	764287	2019-05-01	2019-06-30
100	764288	2019-07-10	2019-07-31
101	764290	2020-02-01	2020-03-31
102	764293	2021-10-01	2021-12-31
103	764294	2022-01-01	2022-01-31