demo, Sql Server - rextester

demo

Language: Layout:

--Sql Server 2014 Express Edition
--Batches are separated by 'go'

WITH TableA AS (
    SELECT '2018-01-01 00:00:00' AS Datetime, 1 AS ID, 11 AS A, 22 AS B, 33 AS C, 44 AS D UNION ALL
    SELECT '2018-01-02 00:00:00', 1, 11, 21, 33, 44 UNION ALL
    SELECT '2018-01-03 00:00:00', 1, 11, 21, 33, 44 UNION ALL
    SELECT '2018-01-04 00:00:00', 1, 11, 21, 33, 44 UNION ALL
    SELECT '2018-01-05 00:00:00', 1, 11, 21, 33, 44 UNION ALL
    SELECT '2018-01-06 00:00:00', 1, 11, 21, 33, 44
),
TableB AS (
    SELECT '2018-02-01 00:00:00' AS Datetime, 2 AS ID, 101 AS E, 212 AS F, 313 AS G, 414 AS H UNION ALL
    SELECT '2018-02-02 00:00:00', 2, 101, 212, 313, 414 UNION ALL
    SELECT '2018-02-03 00:00:00', 2, 101, 212, 313, 414 UNION ALL
    SELECT '2018-02-04 00:00:00', 2, 101, 212, 313, 414 UNION ALL
    SELECT '2018-02-05 00:00:00', 2, 101, 212, 313, 414 UNION ALL
    SELECT '2018-02-06 00:00:00', 2, 101, 212, 313, 414
),
TableC AS (
    SELECT '2018-03-01 00:00:00' AS Datetime, 3 AS ID, 11 AS I, 22 AS J, 33 AS K, 44 AS L UNION ALL
    SELECT '2018-03-02 00:00:00', 3, 11, 22, 33, 44 UNION ALL
    SELECT '2018-03-03 00:00:00', 3, 11, 22, 33, 44 UNION ALL
    SELECT '2018-03-04 00:00:00', 3, 11, 22, 33, 44 UNION ALL
    SELECT '2018-03-05 00:00:00', 3, 11, 22, 33, 44 UNION ALL
    SELECT '2018-03-06 00:00:00', 3, 11, 22, 33, 44
)

SELECT Datetime, ID, A, B, C, D, NULL AS E, NULL AS F, NULL AS G, NULL AS H,
    NULL AS I, NULL AS J, NULL AS K, NULL AS L
FROM TableA
UNION ALL
SELECT Datetime, ID, NULL, NULL, NULL, NULL, E, F, G, H, NULL, NULL, NULL, NULL
FROM TableB
UNION ALL
SELECT Datetime, ID, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, I, J, K, L
FROM TableC
ORDER BY
    ID, Datetime;

View schema
Execution time: 0,02 sec, rows selected: 18, rows affected: 0, absolute service time: 0,22 sec

	Datetime	ID	A	B	C	D	E	F	G	H	I	J	K	L
1	2018-01-01 00:00:00	1	11	22	33	44	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
2	2018-01-02 00:00:00	1	11	21	33	44	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
3	2018-01-03 00:00:00	1	11	21	33	44	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
4	2018-01-04 00:00:00	1	11	21	33	44	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
5	2018-01-05 00:00:00	1	11	21	33	44	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
6	2018-01-06 00:00:00	1	11	21	33	44	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
7	2018-02-01 00:00:00	2	NULL	NULL	NULL	NULL	101	212	313	414	NULL	NULL	NULL	NULL
8	2018-02-02 00:00:00	2	NULL	NULL	NULL	NULL	101	212	313	414	NULL	NULL	NULL	NULL
9	2018-02-03 00:00:00	2	NULL	NULL	NULL	NULL	101	212	313	414	NULL	NULL	NULL	NULL
10	2018-02-04 00:00:00	2	NULL	NULL	NULL	NULL	101	212	313	414	NULL	NULL	NULL	NULL
11	2018-02-05 00:00:00	2	NULL	NULL	NULL	NULL	101	212	313	414	NULL	NULL	NULL	NULL
12	2018-02-06 00:00:00	2	NULL	NULL	NULL	NULL	101	212	313	414	NULL	NULL	NULL	NULL
13	2018-03-01 00:00:00	3	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	11	22	33	44
14	2018-03-02 00:00:00	3	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	11	22	33	44
15	2018-03-03 00:00:00	3	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	11	22	33	44
16	2018-03-04 00:00:00	3	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	11	22	33	44
17	2018-03-05 00:00:00	3	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	11	22	33	44
18	2018-03-06 00:00:00	3	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	11	22	33	44