Stripping the time out of datetime SQL Server 2005 - function

Question

I think I'm going crazy here.
I am trying to do a SP on SQL Server 2005 which takes a date, looks it up in another table and assigns a period number and week number (for financial calendar purposes).
The output needs to hold the date as a string, rather than datetime.
I simply CANNOT get the date to show without the time behind it.
I have tried a couple of methods:
select cast(floor(cast(#CalcDate as float)) as datetime)
I have made a function which converts it into a string and puts it back out again:
CREATE FUNCTION dbo.DateToVarchar (#DateIn datetime)
RETURNS varchar(10)
AS
BEGIN
declare #DD [varchar] (2)
declare #MM [varchar] (2)
declare #YYYY [varchar] (4)
declare #DateOut [varchar] (10)
declare #DDLen [int]
declare #MMLen [int]
set #DD = datepart(dd,#DateIn)
set #DDLen = len(#DD)
set #DD = (case when #DDLen < 2 then '0' + #DD else #DD end)
set #MM = datepart(mm,#DateIn)
set #MMLen = len(#MM)
set #MM = (case when #MMLen < 2 then '0' + #MM else #MM end)
set #YYYY = datepart(yyyy,#DateIn)
set #DateOut = #YYYY + '-' + #MM + '-' + #DD
return #DateOut
END
When I run the above function outside of the SP I get the date back just fine. When I run it through the SP it comes back as 2012-12-30 00:00:00.000
The variable #CalcDate is declared as a varchar(10)
Any ideas?
Thanks in advance
EDIT
Here is the body of the SP so far:
declare #StartDate [datetime]
, #EndDate [Datetime]
, #CalcDate [datetime] --This number will change in the WHILE loop to reflect the increment of days
, #Week [varchar]
, #Period [varchar]
, #i [int]
, #Year [int]
, #CalcDay [int]
, #CalcMonth [int]
, #CalcYear [int]
, #ConcatDate [char] (10)
set #StartDate = '2012-12-30'
set #EndDate = '2013-01-28'
set #Year = 2013
set #i = -1
-- Going to do a while loop here and instead of Week number and Period Number I'm going to do some calculations
set #Week = (Select WeekNum from aaGreensPeriodListTest Where PeriodNum = 1 and WeekNum = 1)
set #Period = (Select PeriodNum from aaGreensPeriodListTest Where PeriodNum = 1 and WeekNum = 1)
set #CalcDate = #StartDate + #i
set #CalcMonth = datepart(mm,#calcdate)
insert into aaGreensPeriodTest(RealDate,GreensYear,GreensPeriod,GreensWeek)
values (#CalcDate,#Year,#Period,#Week)
select #CalcDate as CalcDate, #CalcMonth as CalcMonth

Answer 1

SQL Server 2005 does not support date type without time part.
If your need to get date as a string you can use convert function. For example:
declare #date datetime;
set #date = getdate();
select convert(varchar, #date, 101) -- that will return date in ‘mm/dd/yyyy’ format
If you need a datetime variable without time part for some calculations, you can use an expression below:
declare #date datetime;
set #date = getdate();
select dateadd(dd, datediff(dd, 0, #date), 0)

Answer 2

As per http://msdn.microsoft.com/en-ca/library/ms187928.aspx, you cannot cast float->date directly. It's simply not supporte. But you can cast a datetime->date, so you'll have to double-cast. Or given your example, triple-cast:
CAST(CAST(CAST(#CalcDate AS float) AS datetime) AS date)