Not sure if you're just trying to get the beginning and end of a month or the day that the month begins and ends on.

CREATE FUNCTION [dbo].[dbFunc_GetFirstDayOfMonth]

( @pInputDate DATETIME )

RETURNS DATETIME

BEGIN

RETURN CAST(CAST(YEAR(@pInputDate) AS VARCHAR(4)) + '/' +

CAST(MONTH(@pInputDate) AS VARCHAR(2)) + '/01' AS DATETIME)

END

CREATE FUNCTION [dbo].[dbFunc_GetLastDayOfMonth]

(@LoadID AS Int)

RETURNS DATETIME

BEGIN

DECLARE @Year AS INT

DECLARE @Month AS INT

DECLARE @LastDay AS INT

SET @Year = LEFT(@LoadID, 4)

SET @Month = RIGHT(@LoadID, 2)

SET @LastDay = CASE @Month

WHEN 1 THEN 31

WHEN 2 THEN CASE WHEN @Year % 4 = 0 THEN 29 ELSE 28 END

WHEN 3 THEN 31

WHEN 4 THEN 30

WHEN 5 THEN 31

WHEN 6 THEN 30

WHEN 7 THEN 31

WHEN 8 THEN 31

WHEN 9 THEN 30

WHEN 10 THEN 31

WHEN 11 THEN 30

WHEN 12 THEN 31

END

RETURN CAST

(CASE WHEN LEN(@Month) = 1

THEN '0' + CAST(@Month AS CHAR(1)) ELSE

CAST(@Month AS CHAR(2)) END + '/' + CAST(@LastDay AS CHAR(2)) + '/' + CAST(@Year AS CHAR(4)) AS DATETIME)

END