SQL Server 2017

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE T
    ([Domain] varchar(5), [Baseline] datetime, [PlanningPeriod] datetime, [Actual] int)
;
    
INSERT INTO T
    ([Domain], [Baseline], [PlanningPeriod], [Actual])
VALUES
    ('Dom 1', '2001-01-18 00:00:00', '2018-01-01 00:00:00', 10),
    ('Dom 1', '2001-01-18 00:00:00', '2018-01-02 00:00:00', 20),
    ('Dom 1', '2001-01-18 00:00:00', '2018-01-03 00:00:00', 25),
    ('Dom 1', '2001-01-18 00:00:00', '2018-01-04 00:00:00', 24),
    ('Dom 1', '2001-02-18 00:00:00', '2018-01-02 00:00:00', 60),
    ('Dom 1', '2001-02-18 00:00:00', '2018-01-03 00:00:00', 20),
    ('Dom 1', '2001-02-18 00:00:00', '2018-01-05 00:00:00', 40),
    ('Dom 1', '2001-02-18 00:00:00', '2018-01-12 00:00:00', 70),
    ('Dom 1', '2001-03-18 00:00:00', '2018-01-03 00:00:00', 11),
    ('Dom 1', '2001-03-18 00:00:00', '2018-01-04 00:00:00', 12),
    ('Dom 1', '2001-03-18 00:00:00', '2018-01-12 00:00:00', 18),
    ('Dom 1', '2001-04-18 00:00:00', '2018-01-04 00:00:00', 40),
    ('Dom 1', '2001-04-18 00:00:00', '2018-01-05 00:00:00', 25),
    ('Dom 1', '2001-04-18 00:00:00', '2018-01-06 00:00:00', 15)
;

14 rows affected

domain	baseline	planningperiod	actual	cumilativeactual
Dom 1	18/01/2001 00:00:00	01/01/2018 00:00:00	10	0
Dom 1	18/01/2001 00:00:00	02/01/2018 00:00:00	20	30
Dom 1	18/01/2001 00:00:00	03/01/2018 00:00:00	25	55
Dom 1	18/01/2001 00:00:00	04/01/2018 00:00:00	24	79
Dom 1	18/02/2001 00:00:00	02/01/2018 00:00:00	60	79
Dom 1	18/02/2001 00:00:00	03/01/2018 00:00:00	20	80
Dom 1	18/02/2001 00:00:00	05/01/2018 00:00:00	40	120
Dom 1	18/02/2001 00:00:00	12/01/2018 00:00:00	70	190
Dom 1	18/03/2001 00:00:00	03/01/2018 00:00:00	11	190
Dom 1	18/03/2001 00:00:00	04/01/2018 00:00:00	12	23
Dom 1	18/03/2001 00:00:00	12/01/2018 00:00:00	18	41
Dom 1	18/04/2001 00:00:00	04/01/2018 00:00:00	40	41
Dom 1	18/04/2001 00:00:00	05/01/2018 00:00:00	25	65
Dom 1	18/04/2001 00:00:00	06/01/2018 00:00:00	15	80