How to query all months from January to December - sql

Question

How to query all months from January to December for all values. The values of 0 should also be presented in query result.
My query:
SELECT *
FROM
(SELECT
MONTH(begin_ts) AS [Month],
SUM(CASE
WHEN bmktonr = '7'
THEN dauer
ELSE reserve1
END) + SUM(CASE
WHEN bmktonr = '11'
THEN dauer
ELSE reserve1
END) AS Prozess_Verfügbarkeit,
SUM(CASE
WHEN bmktonr = '1'
THEN dauer
ELSE reserve1
END) + SUM(CASE
WHEN bmktonr = '2'
THEN dauer
ELSE reserve1
END) AS Verfügbarkeit
FROM
[hydra1].[hydadm].[v_ereignis]
WHERE
masch_nr = 'FIMI1'
AND YEAR(begin_ts) = YEAR(CURRENT_TIMESTAMP)
GROUP BY
MONTH(begin_ts)) T
INNER JOIN
(SELECT
p.masch_nr,
SUM(b.ruest_zeit) AS SOLLRüsten,
SUM(b.bearb_zeit) AS SOLLProduktion,
SUM(b.ruest_zeit_zuschl) AS SOLLZuschlag,
SUM(p.bmk_07) AS ISTRüsten,
SUM(p.bmk_11) AS ISTProduktion,
MONTH(prot_dat) AS Month
FROM
[hydra1].[hydadm].[v_auftrag_status] p
JOIN
[hydra1].[hydadm].[v_auftrags_bestand] b ON b.auftrag_nr = p.auftrag_nr
WHERE
p.masch_nr = 'GEORG'
AND a_status = 'E'
AND YEAR(prot_dat) = YEAR(CURRENT_TIMESTAMP)
GROUP BY
p.masch_nr, MONTH(prot_dat)) T1 ON T.Month = T1.Month
ORDER BY
T.Month
This is how it should look then:
Month | Prozess_Verfügbarkeit | Verfügbarkeit
------+-----------------------+--------------
1 | 344 | 4556
2 | 0 | 0
3 | 0 | 0
4 | 0 | 0
5 | 0 | 0
6 | 0 | 0
7 | 0 | 0
8 | 0 | 0
9 | 0 | 0
10 | 0 | 0
11 | 0 | 0
12 | 0 | 0
Thanks a lot.

Answer 1

Something like this ought to do it:
WITH months AS (
SELECT 1 AS month_number
UNION ALL SELECT 2
UNION ALL SELECT 3
...
UNION ALL SELECT 12
)
SELECT months.month_number
, your_query.thing_a
, your_query.thing_b
FROM months
LEFT
JOIN your_query
ON your_query.Month = months.month_number
;