Create Calendar by T-SQL

Introduction

This SQL statement can generate a calendar by inputting a month and a year.

Background

In my work, I usually need to generate a calendar by inputting a month and a year, so I write the following code to do it.

Using the Code

DECLARE @Month AS INT = 4 --Set the MONTH for which you want to generate the Calendar.
DECLARE @Year AS INT = 2013 --Set the YEAR for which you want to generate the Calendar.
DECLARE @StartDate AS DATETIME = CONVERT(VARCHAR,@Year) + RIGHT('0' + CONVERT(VARCHAR,@Month),2) + '01'
DECLARE @EndDate AS DATETIME = DATEADD(DAY,-1,DATEADD(MONTH,1,@StartDate));

SELECT
SUM(CASE WHEN DATEPART(DW, DATEADD(DD,number,@StartDate)) = 1 _
THEN DATEPART(DAY, DATEADD(DD,NUMBER,@StartDate)) END) AS Sunday
,SUM(CASE WHEN DATEPART(DW, DATEADD(DD,number,@StartDate)) = 2 _
THEN DATEPART(DAY, DATEADD(DD,NUMBER,@StartDate)) END) AS Monday
,SUM(CASE WHEN DATEPART(DW, DATEADD(DD,number,@StartDate)) = 3 _
THEN DATEPART(DAY, DATEADD(DD,NUMBER,@StartDate)) END) AS Tuesday
,SUM(CASE WHEN DATEPART(DW, DATEADD(DD,number,@StartDate)) = 4 _
THEN DATEPART(DAY, DATEADD(DD,NUMBER,@StartDate)) END) AS Wednesday
,SUM(CASE WHEN DATEPART(DW, DATEADD(DD,number,@StartDate)) = 5 _
THEN DATEPART(DAY, DATEADD(DD,NUMBER,@StartDate)) END) AS Thursday
,SUM(CASE WHEN DATEPART(DW, DATEADD(DD,number,@StartDate)) = 6 _
THEN DATEPART(DAY, DATEADD(DD,NUMBER,@StartDate)) END) AS Friday
,SUM(CASE WHEN DATEPART(DW, DATEADD(DD,number,@StartDate)) = 7 _
THEN DATEPART(DAY, DATEADD(DD,NUMBER,@StartDate)) END) AS Saturday
FROM master.dbo.spt_values v
WHERE DATEADD(DD,number,@StartDate) BETWEEN @StartDate _
AND DATEADD(DAY,-1,DATEADD(MONTH,1,@StartDate))
AND v.type = 'P'
GROUP BY DATEPART(WEEK, DATEADD(DD,number,@StartDate))