CREATE TABLE [#a](
	[id] [int] NOT NULL,
	[recorddate] [date] NULL,
	[myvalue] [int] NULL,
) ON [PRIMARY]

GO

INSERT INTO [#a] (id, [recorddate], [myvalue])
SELECT 1,'2012-01-02',10 UNION ALL
SELECT 2,'2012-01-13',20 UNION ALL
SELECT 3,'2012-02-02',30 UNION ALL
SELECT 4,'2012-02-24',40 UNION ALL
SELECT 5,'2012-08-02',50 UNION ALL
SELECT 6,'2012-12-01',60 UNION ALL
SELECT 7,'2012-12-28',70

CREATE TABLE [#a](
	[id] [int] NOT NULL,
	[recorddate] [date] NULL,
	[myvalue] [int] NULL,
) ON [PRIMARY]

GO

INSERT INTO [#a] (id, [recorddate], [myvalue])
SELECT 1,'2012-01-02',10 UNION ALL
SELECT 2,'2012-01-13',20 UNION ALL
SELECT 3,'2012-02-02',30 UNION ALL
SELECT 4,'2012-02-24',40 UNION ALL
SELECT 5,'2012-08-02',50 UNION ALL
SELECT 6,'2012-12-01',60 UNION ALL
SELECT 7,'2012-12-28',70


WITH myCTE (c)
AS
(
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-1-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-2-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-3-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-4-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-5-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-6-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-7-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-8-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-9-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-10-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-11-1' AS DATE) AS c
	UNION ALL
	SELECT CAST(CAST(YEAR(GETDATE()) AS CHAR(4))+'-12-1' AS DATE) AS c
)
SELECT DISTINCT c, SUM(myvalue) 
FROM myCTE LEFT JOIN #a  ON myCTE.c=#a.CAST(YEAR(#a.recorddate) as CHAR(4))+'-'+CAST(MONTH(#a.recorddate) as CHAR(2))+'-'+'01' 
GROUP BY c

DROP TABLE #a

WITH CTE(N) AS (SELECT 1 FROM (VALUES(1),(1),(1),(1),(1),(1),(1),(1),(1),(1))a(N)),
CTE2(N) AS (SELECT 1 FROM CTE x CROSS JOIN CTE y),
CTE3(N) AS (SELECT 1 FROM CTE2 x CROSS JOIN CTE2 y),
CTE4(N) AS (SELECT 1 FROM CTE3 x CROSS JOIN CTE3 y),
CTE5(N) AS (SELECT 1 FROM CTE4 x CROSS JOIN CTE4 y),
CTE6(N) AS (SELECT 0 UNION ALL
            SELECT TOP 97199 ROW_NUMBER() OVER(ORDER BY (SELECT NULL))
            FROM CTE5),
TALLY(N) AS (SELECT DATEADD(month, N, 0)
             FROM CTE6)
SELECT a.N AS recorddate, ISNULL(b.myValue,0) AS myValue
FROM TALLY a
OUTER APPLY (SELECT DATEADD(month, DATEDIFF(month, 0, [recorddate]), 0), SUM([myvalue])
             FROM [#a] c
             WHERE DATEADD(month, DATEDIFF(month, 0, [recorddate]), 0) = a.N
             GROUP BY DATEADD(month, DATEDIFF(month, 0, [recorddate]), 0)
			) b(recorddate,myValue)
CROSS APPLY (SELECT MIN(DATEADD(month, DATEDIFF(month, 0, [recorddate]), 0)),
             MAX(DATEADD(month, DATEDIFF(month, 0, [recorddate]), 0))
             FROM [#a]) d(minDate,maxDate)
WHERE a.N >= d.minDate AND a.N <= d.maxDate;

WITH CTE(N) AS (SELECT 1 FROM (VALUES(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) a(N)),
CTE2(N) AS (SELECT 1 FROM CTE x CROSS JOIN CTE y),
CTE3(N) AS (SELECT 1 FROM CTE2 x CROSS JOIN CTE2 y),
CTE4(N) AS (SELECT 1 FROM CTE3 x CROSS JOIN CTE3 y),
CTE5(N) AS (SELECT 1 FROM CTE4 x CROSS JOIN CTE4 y),
CTE6(N) AS (SELECT 0 UNION ALL
            SELECT TOP 97199 ROW_NUMBER() OVER(ORDER BY (SELECT NULL))
            FROM CTE5),
TALLY(N) AS (SELECT DATEADD(month, N, 0)
             FROM CTE6)
SELECT a.N AS recorddate, ISNULL(b.myValue,0) AS myValue
FROM TALLY a
OUTER APPLY (SELECT DATEADD(month, DATEDIFF(month, 0, f.recorddate), 0), SUM(e.numvalue)
             FROM admin_tasks as e INNER JOIN admin_tasks as f ON e.id=f.numvalue
             WHERE DATEADD(month, DATEDIFF(month, 0, f.recorddate), 0) = a.N AND f.actionid=5 AND f.numtype=1
             GROUP BY DATEADD(month, DATEDIFF(month, 0, f.recorddate), 0)
			) b(recorddate,myValue)
CROSS APPLY (SELECT MIN(DATEADD(month, DATEDIFF(month, 0, h.recorddate), 0)),
             MAX(DATEADD(month, DATEDIFF(month, 0, h.recorddate), 0))
             FROM admin_tasks as g INNER JOIN admin_tasks as h ON g.id=h.numvalue WHERE h.actionid=5 AND h.numtype=1) d(minDate,maxDate)
WHERE a.N >= d.minDate AND a.N <= d.maxDate
ORDER BY recorddate ASC

(11 row(s) affected)
Table 'admin_tasks'. Scan count 17, logical reads 8099, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 11, logical reads 28546, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

 SQL Server Execution Times:
   CPU time = 187 ms,  elapsed time = 257 ms.
SQL Server parse and compile time: 
   CPU time = 0 ms, elapsed time = 0 ms.

SELECT TOP 97199 ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM CTE5 

SELECT TOP 97199 ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) FROM CTE5 

CTE6(N) AS (SELECT 0 UNION ALL
            SELECT TOP 611 ROW_NUMBER() OVER(ORDER BY (SELECT NULL))
            FROM CTE5),
TALLY(N) AS (SELECT DATEADD(month, N, CAST('2000' AS DATETIME))
             FROM CTE6)