Procedure to count days between two dates - tsql

Question

Seems redundant, but I am trying to count rows in a temporary created table inside a procedure.
(Note: table is most likely coded wrong) The #rows variable is needed to be counted and should output the exact amount of days in a year from the #StartDate variable. (this is including leap years).
The table created should also INSERT date VALUES for each day for exactly a year after the #StartDate variable.
TEMPORARY TABLE required in this assignment. Sorry people, but that is what the teacher is asking for.
FYI: I'm a novice, and help would be greatly appreciated :)
CREATE PROCEDURE usp_DateLookup
#StartDate DATE,
#Rows INT OUTPUT
AS
DECLARE #countIndex INT
DECLARE #yearDate DATE
DECLARE #todaysDate DATE
SET #yearDate = DATEADD(YEAR, 1,#StartDate)
SET #todaysDate = GETDATE()
BEGIN
CREATE TABLE #DateLookup
(
DateID INT IDENTITY (1,1),
DateDescription DATE
)
WHILE (SELECT DATEDIFF(DD,#StartDate, #yearDate) FROM #DateLookup) <= 366
BEGIN
SET #countIndex = #countIndex +1
INSERT #DateLookup (DateDescription)
VALUES (DAY(#todaysDate)+ #countIndex)
END
SET #Rows = (SELECT COUNT(DateDescription) FROM #DateLookup)
END
GO
DECLARE #StartDate DATE
DECLARE #Rows INT
SET #StartDate = '2012-05-06'
EXEC usp_DateLookup #StartDate, #Rows OUTPUT
PRINT CONVERT(NVARCHAR,#Rows)

Answer 1

I am not sure why you need #DateLookup table? You can get the number of days in a year as follows (Better to use as a function)
CREATE PROCEDURE usp_DateLookup
#StartDate DATE,
#Rows INT OUTPUT
AS
--DECLARE #StartDate DATE = '2012-05-06'
select #Rows = datediff(day,#StartDate,dateadd(year,1,#StartDate))
END
GO;
As per your comment ( You need the temp table for the assignment), you could do it without a loop as below; SQL-DEMO
CREATE PROCEDURE usp_DateLookup
#StartDate DATE,
#Rows INT OUTPUT
AS
--DECLARE #StartDate DATE = '2012-05-06'
DECLARE #Rows INT = DATEDIFF(day,#StartDate,dateadd(year,1,#StartDate))
CREATE TABLE #DateLookup
(
DateID INT IDENTITY (1,1),
DateDescription DATE
)
;with Digits as (
select Digit
from (
values (0), (1), (2), (3), (4), (5),
(6), (7), (8), (9)) as t(Digit)),
Numbers as (
select u.Digit + t.Digit*10 +h.Digit*100 as Number
from Digits u
cross join Digits t
cross join Digits h
)
insert into #DateLookup
select dateadd(day,Number+1,#StartDate) from Numbers where Number < #Rows
order by Number
END
GO;
Also you need a LOOP? Your INSERT fails since you trying to enter a number (DAY(#todaysDate)+ #countIndex) into DATE field
INSERT #DateLookup (DateDescription)
VALUES ('this-should-be-a-valid-date')