SQL Server 2019

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select *
into t
from (values (10001, convert(datetime, '2020-04-01 00:00:00.000'), convert(datetime, '2020-05-25 00:00:00.000')),
             (10001, convert(datetime, '2020-05-26 00:00:00.000'), convert(datetime, '2020-07-15 00:00:00.000')),
             (10001, convert(datetime, '2020-07-17 00:00:00.000'), convert(datetime, '2020-08-15 00:00:00.000')),
             (10001, convert(datetime, '2020-08-16 00:00:00.000'), convert(datetime, '2020-10-15 00:00:00.000')),
             (10001, convert(datetime, '2020-10-16 00:00:00.000'), convert(datetime, '2020-12-31 00:00:00.000')),
             (10002, convert(datetime, '2020-05-01 00:00:00.000'), convert(datetime, '2020-05-29 00:00:00.000')),
             (10002, convert(datetime, '2020-05-30 00:00:00.000'), convert(datetime, '2020-07-08 00:00:00.000')),
             (10002, convert(datetime, '2020-07-09 00:00:00.000'), convert(datetime, '2020-10-01 00:00:00.000')),
             (10002, convert(datetime, '2020-10-03 00:00:00.000'), convert(datetime, '2020-12-31 00:00:00.000'))
) v(Id, startDate, EndDate)

9 rows affected

id	(No column name)	(No column name)
10001	2020-04-01 00:00:00.000	2020-07-15 00:00:00.000
10002	2020-05-01 00:00:00.000	2020-10-01 00:00:00.000
10001	2020-07-17 00:00:00.000	2020-12-31 00:00:00.000
10002	2020-10-03 00:00:00.000	2020-12-31 00:00:00.000