declare @A table (userid int, Channel1_Date datetime, type1_id int, Channel2_Date datetime, type2_id int,	profile_id int)

insert @A values(345,	'2019-01-23 00:00',	1,	'2018-10-19 13:30',	2,	435)
insert @A values(345,	'2018-10-25 13:30',	3,	'2019-01-25 00:00',	4,	750)
insert @A values(345,	'2018-10-22 13:30',	2,	NULL,	NULL,	NULL)
insert @A values(23,	'2019-01-26 00:00',	2,	'2019-01-25 00:00',	1,	223)
insert @A values(23,	'2019-01-27 00:00',	1,	NULL,	NULL,	NULL)
insert @A values(23,	NULL,	NULL,	'2019-01-23 00:00',	3,	224)

select * from @A  

userid	Channel1_Date	             type1_id	Channel2_Date	             type2_id	profile_id
345,	2018-10-22 13:30:00.000,	2,	2018-10-19 13:30:00.000,	2,	435
23,	2019-01-26 00:00:00.000,	2,	2019-01-23 00:00:00.000,	3,	224

select  *
from @A a
order by row_number() over(partition by a.userid order by a.Channel1_Date)

select top 1 with ties a.userid , a.Channel1_Date , a.type1_id, b.Channel2_Date , b.type2_id ,	b.profile_id
from @A a left join @A b on (a.userid=b.userid)
where a.Channel1_Date is not null and b.Channel2_Date is not null
order by row_number() over(partition by a.userid order by a.Channel1_Date asc, b.Channel2_Date asc)