SQL Query to return records grouped by Week, Month, and Year. Weeks with no records should return 0

Question

Given the following data:

ID      CreatedDate
ID1     2014-06-04 01:40:56.880
ID8     2014-06-05 00:27:02.403
ID6     2014-06-04 01:51:47.060
ID7     2014-06-05 00:25:35.187
ID4     2014-06-04 01:48:44.157
ID10    2014-06-05 00:28:33.993
ID43    2014-06-16 05:17:18.803
ID72    2014-06-20 04:00:07.733
.
.
.
Etc.

I need to write a query that will group records by week, month, and year. A count of the number of records that were created in a particular week needs to be returned. The output should be as follows:

Week    Month   Year    Count
23         6    2014    16
24         6    2014    0
25         6    2014    7
26         6    2014    0
27         7    2014    25
28         7    2014    18  
.
.
.
etc.

Where a week has no records the count should return 0. Only records that were created within the past 12 months from the time the query is executed should be return. The query will be executed each week to produce a report.

Answer 1

Demo purpose I am using the Table name as [DBO].[FACTINTERNETSALES] and the column [ORDERDATE] For you the Column will be [CreatedDate]. Fyi, This is done in SQL Server.

DECLARE @START INT,
        @END INT

SELECT @START   = CAST(CAST(MIN(ORDERDATE) AS DATETIME) AS INT) FROM [DBO].[FACTINTERNETSALES] 
SELECT @END     = CAST(CAST(MAX(ORDERDATE) AS DATETIME) AS INT) FROM [DBO].[FACTINTERNETSALES] 

--SELECT @START,@END

DECLARE @DATEDIM TABLE (ID INT IDENTITY(1,1) PRIMARY KEY, DATED DATETIME)
WHILE @START <= @END
BEGIN
    INSERT INTO @DATEDIM VALUES (CAST(@START AS DATETIME))
    SET @START = @START  + 1 
END

SELECT      LU.WEEK,LU.MONTH,LU.YEAR,ISNULL(MAIN.COUNT,0) [COUNT]
FROM        (
            SELECT      DATEPART(WEEK,DATED) [WEEK],DATEPART(MONTH,DATED) [MONTH],DATEPART(YEAR,DATED) [YEAR] 
            FROM        @DATEDIM
            GROUP BY    DATEPART(WEEK,DATED),DATEPART(MONTH,DATED),DATEPART(YEAR,DATED)) LU
LEFT JOIN
            (
            SELECT  [YEAR],[MONTH],[WEEK],COUNT(*) [COUNT] FROM
            (SELECT DATEPART(YEAR,ORDERDATE) [YEAR],
                    DATEPART(MONTH,ORDERDATE) [MONTH],
                    DATEPART(WEEK,ORDERDATE) [WEEK]
            FROM    [DBO].[FACTINTERNETSALES] ) LUINNER
            GROUP BY [YEAR],[MONTH],[WEEK]) MAIN 
ON
            LU.MONTH = MAIN.MONTH AND
            LU.YEAR = MAIN.YEAR AND
            LU.WEEK = MAIN.WEEK
ORDER BY    LU.YEAR,LU.MONTH,LU.WEEK

Result: (Only a portion of result)