DROP PROCEDURE weirddatestuff
GO

CREATE PROCEDURE weirddatestuff

--SET DATEFORMAT YMD EXEC weirddatestuff '2001/04/01','2001/01/01',15

@startdate DATETIME,
@datefrom DATETIME,
@months INT

AS

SET DATEFORMAT YMD

SELECT @startdate = CAST(DATEPART(YY,@startdate) AS VARCHAR(4)) + '/' + CAST(DATEPART(MM,@startdate) AS VARCHAR(2)) + '/01'

--Create the table to hold all this crap.
CREATE TABLE #weirddatepopulation(
	IhatecolumnscalledID INT IDENTITY(1,1),
	PackID VARCHAR(4), --Why is this varchar(4)?  It should be an INT.
	DateFrom DATETIME,
	DateTo DATETIME)

--Hold your PackID series.
DECLARE @packer TABLE(PackID INT) --Love these names.

INSERT @packer(PackID)
	SELECT 1 UNION ALL
	SELECT 2 UNION ALL
	SELECT 3 UNION ALL
	SELECT 4

--Populate a date table with the appropriate dates.
DECLARE @datestuff TABLE(datestuffed DATETIME)

DECLARE 
	@min INT,
	@startdatemid DATETIME,
	@startdateend DATETIME,
	@minplusone INT

SELECT @min = 0

WHILE @min < @months
BEGIN

	SELECT @minplusone = @min + 1

	SELECT 
		@startdatemid = DATEADD(DD,14,DATEADD(MM,@min,@startdate)),
		@startdateend = DATEADD(DD,-1,DATEADD(MM,@minplusone,@startdate))

	INSERT @datestuff(datestuffed)
		SELECT @startdatemid  UNION ALL
		SELECT @startdateend

SELECT @min = @min + 1
END

INSERT #weirddatepopulation(
	PackID,
	DateFrom,
	DateTo)

	SELECT
		p.PackID,
		@datefrom,
		ds.datestuffed
	FROM
		@datestuff ds
		CROSS JOIN @packer p
	ORDER BY
		ds.datestuffed,
		p.PackID

SELECT
	IhatecolumnscalledID,
	PackID,
	DateFrom,
	DateTo
FROM 
	#weirddatepopulation
GO