INSERT INTO [SupportTracker].[dbo].[DashboardRecords]
SELECT [bg_id]
      ,[bg_short_desc]
      ,[bg_reported_date]
      ,[bg_status_updated_date]
      ,[us_firstname]
      ,[us_lastname]
      ,[LastUpdatedUserFirstname]
      ,[LastUpdatedUserLastname]
      ,[st_name]
      ,[pr_name]
      ,[ct_name]
      ,[pj_name]
      ,[AssignedUserFirstname]
      ,[AssignedUserLastname]
      ,[bg_project]
      ,[no_of_hours]
      ,[BugType]
      ,[SubType]
      ,[Device]
      ,[pj_parent_id]
FROM [SupportTracker].[dbo].[ViewIssueListwBugTypeNDevice]
WHERE
     bg_reported_date between '2012-12-01 00:00:00.000' AND '2012-12-31 23:59:59.999'
     AND bg_id NOT IN (SELECT bg_id FROM [SupportTracker].[dbo].[DashboardRecords])
ORDER BY bg_reported_date ASC

SELECT DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()), 0);

SELECT DATEADD(MONTH, 1+DATEDIFF(MONTH, 0, GETDATE()), 0);

SELECT DATEADD(MONTH, 1+DATEDIFF(MONTH, 0, DATEADD(DAY, -1, GETDATE())), 0);

...
FROM SupportTracker.dbo.ViewIssueListwBugTypeNDevice AS v
WHERE NOT EXISTS
(
  SELECT 1 FROM SupportTracker.dbo.DashboardRecords
    WHERE bg_id = v.bg_id
)
AND v.bg_reported_date >= DATEADD(MONTH, 0, DATEDIFF(MONTH, 0, DATEADD(DAY, -1, GETDATE()))
AND v.bg_reported_date < DATEADD(MONTH, 1, DATEDIFF(MONTH, 0, DATEADD(DAY, -1, GETDATE()));

@Month DATE = NULL
...

  SET @Month = DATEADD(MONTH, 0, DATEDIFF(MONTH, 0, COALESCE(@Month,
    DATEADD(DAY, -1, GETDATE())));

...
FROM SupportTracker.dbo.ViewIssueListwBugTypeNDevice AS v
WHERE NOT EXISTS
(
  SELECT 1 FROM SupportTracker.dbo.DashboardRecords
    WHERE bg_id = v.bg_id
)
AND v.bg_reported_date >= @Month
AND v.bg_reported_date < DATEADD(MONTH, 1, @Month);

SELECT FirstOfThisMonth = DATEADD(DAY, 1-DAY(GETDATE()), CONVERT(date, GETDATE()));

DECLARE @MonthStart DATETIME
DECLARE @Date  DATETIME
DECLARE @next DATETIME
-- create the required date. because today is the 21st i subtracted month.
-- since you're running the job on the first day of the new month,
-- you may want to change MONTH to DAY. however, if the job fails that change
-- that may cause you some problems
SET @Date = DATEADD(MONTH,-1,DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()), 0))

-- get the first day of the month of the date specified
SET @MonthStart = DATEADD(DAY, 1, @Date - DAY(@Date) + 1) -1

-- get the first day of next month
SET @Next = DATEADD(MONTH,1,@MonthStart)

-- prove to yourself that these dates are correct (sanity check)
SELECT @MonthStart, @next

INSERT INTO [SupportTracker].[dbo].[DashboardRecords]
SELECT [bg_id]
      ,[bg_short_desc]
      ,[bg_reported_date]
      ,[bg_status_updated_date]
      ,[us_firstname]
      ,[us_lastname]
      ,[LastUpdatedUserFirstname]
      ,[LastUpdatedUserLastname]
      ,[st_name]
      ,[pr_name]
      ,[ct_name]
      ,[pj_name]
      ,[AssignedUserFirstname]
      ,[AssignedUserLastname]
      ,[bg_project]
      ,[no_of_hours]
      ,[BugType]
      ,[SubType]
      ,[Device]
      ,[pj_parent_id]
FROM [SupportTracker].[dbo].[ViewIssueListwBugTypeNDevice] b
LEFT JOIN [SupportTracker].[dbo].[DashboardRecords] d
    ON b.bg_id = d.bg_id
WHERE b.bg_reported_date >= @MonthStart and b.bg_reported_date < @Next
    AND d.[bg_short_desc] IS NULL

INSERT INTO [SupportTracker].[dbo].[DashboardRecords]

SELECT [bg_id]
      ,[bg_short_desc]
      ,[bg_reported_date]
      ,[bg_status_updated_date]
      ,[us_firstname]
      ,[us_lastname]
      ,[LastUpdatedUserFirstname]
      ,[LastUpdatedUserLastname]
      ,[st_name]
      ,[pr_name]
      ,[ct_name]
      ,[pj_name]
      ,[AssignedUserFirstname]
      ,[AssignedUserLastname]
      ,[bg_project]
      ,[no_of_hours]
      ,[BugType]
      ,[SubType]
      ,[Device]
      ,[pj_parent_id]
FROM [SupportTracker].[dbo].[ViewIssueListwBugTypeNDevice] b
WHERE b.bg_reported_date >= @MonthStart and b.bg_reported_date < @Next
    AND NOT EXISTS (SELECT 1 FROM [SupportTracker].[dbo].[DashboardRecords] d
        WHERE b.bg_id = d.bg_id);