SQL Server 2019

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create table atable (subscriberid int, datecreated date)

insert into atable values 
(1, '20220101'), (1, '20220201'), (1, '20220301'),
(2, '20220101'), (2, '20220201'), (2, '20220601')

select * from atable

subscriberid
datecreated

1
2022-01-01

1
2022-02-01

1
2022-03-01

2
2022-01-01

2
2022-02-01

2
2022-06-01

select t.subscriberid
from   ( select t.subscriberid,
                t.datecreated,
                lag(t.datecreated) over (partition by t.subscriberid order by t.subscriberid, t.datecreated) prevdate
         from   atable t
       ) t
where datediff(day, prevdate, datecreated) >= 90
      
subscriberid

2

drop table atable

subscriberid	datecreated
1	2022-01-01
1	2022-02-01
1	2022-03-01
2	2022-01-01
2	2022-02-01
2	2022-06-01