SQL Server 2022

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create table mytable (
  Id	int,
  Type	varchar(20),
  Source	 varchar(20),
  Date date
);

insert into mytable values
(11,	'E-mail',	'External',	'2024-02-12'),
(11,	'E-mail',	'External',	'2024-02-13'),
(11,	'E-mail',	'Customer',	'2024-02-10');
3 rows affected

select *, row_number() over (partition by Id, Type, Source order by Date) as rn
from mytable


Id
Type
Source
Date
rn


11
E-mail
Customer
2024-02-10
1

11
E-mail
External
2024-02-12
1

11
E-mail
External
2024-02-13
2


select Id,
       max(case when Source = 'External' then Date end) as 'External source Date',
       max(case when Source = 'Customer' then Date end) as 'Customer source Date'
from (
  select *, row_number() over (partition by Id, Type, Source order by Date) as rn
  from mytable
) as s
group by Id, Type, rn


Id
External source Date
Customer source Date


11
2024-02-12
2024-02-10

11
2024-02-13
null


Warning: Null value is eliminated by an aggregate or other SET operation.

Id	Type	Source	Date	rn
11	E-mail	Customer	2024-02-10	1
11	E-mail	External	2024-02-12	1
11	E-mail	External	2024-02-13	2