get startdate and enddate from specified week of the month - sql-server-2008

Question

I need to find start date and end date from specified (1/2/3/4/5) week of month. So that I can get the records where Date_Created comes in specified (1/2/3/4/5) Week.
For example if
I choose 1st week of febuary 2013 then
I want startdate = 2/1/2013 and enddate = 2/2/2013
I choose 2nd week of febuary 2013 then
I want startdate = 2/3/2013 and enddate = 2/9/2013
and similary for rest weeks.
I have SQL Server 2008 at Database Side. If anyone have Idea then Please Share.

Answer 1

Here is a query to get all weeks start and end dates for given month. So you can select from this query week you need:
SQLFiddle example
with C(i) as
( select CAST('2013-02-01' as datetime) i
UNION ALL
select DATEADD (day,1,i) i from C
where DATEADD (day,1,i)
<DATEADD(month,1,'2013-02-01')
), C1 as
(
select DATEPART(WEEK,i)-DATEPART(WEEK,'2013-02-01')+1 WeekOfMonth,i from C
)
select WeekOfMonth,min(i) StartDate, max(i) EndDate from C1 group by WeekOfMonth

Answer 2

I wrote a procedure to solve my problem which will take week no(1/2/3/4/5) as input and will return startdate and enddate
ALTER PROCEDURE dbo.SPGetStartAndEndDateofSpcifiedWeek
#Week int
AS
SET NOCOUNT ON
DECLARE #date DateTime
DECLARE #currdate DateTime
DECLARE #startdate DateTime
DECLARE #enddate DateTime
DECLARE #CurrWeek int
/*SET #date = CONVERT(date,GETDATE())*/
SET #currdate = CONVERT(date,GETDATE())
SET #CurrWeek = datediff(week, dateadd(week, datediff(week, 0, dateadd(month, datediff(month, 0, GETDATE()), 0)), 0), GETDATE() - 1) + 1
IF (#Week = 1)
BEGIN
IF (#CurrWeek = 1)
BEGIN SET #date = #currdate END
IF (#CurrWeek = 2)
BEGIN SET #date = #currdate - 7 END
IF (#CurrWeek = 3)
BEGIN SET #date = #currdate - 14 END
IF (#CurrWeek = 4)
BEGIN SET #date = #currdate - 21 END
IF (#CurrWeek = 5)
BEGIN SET #date = #currdate - 28 END
END
IF (#Week = 2)
BEGIN
IF (#CurrWeek = 1)
BEGIN SET #date = #currdate + 7 END
IF (#CurrWeek = 2)
BEGIN SET #date = #currdate END
IF (#CurrWeek = 3)
BEGIN SET #date = #currdate - 7 END
IF (#CurrWeek = 4)
BEGIN SET #date = #currdate - 14 END
IF (#CurrWeek = 5)
BEGIN SET #date = #currdate - 21 END
END
IF (#Week = 3)
BEGIN
IF (#CurrWeek = 1)
BEGIN SET #date = #currdate + 14 END
IF (#CurrWeek = 2)
BEGIN SET #date = #currdate + 7 END
IF (#CurrWeek = 3)
BEGIN SET #date = #currdate END
IF (#CurrWeek = 4)
BEGIN SET #date = #currdate - 7 END
IF (#CurrWeek = 5)
BEGIN SET #date = #currdate - 14 END
END
IF (#Week = 4)
BEGIN
IF (#CurrWeek = 1)
BEGIN SET #date = #currdate + 21 END
IF (#CurrWeek = 2)
BEGIN SET #date = #currdate + 14 END
IF (#CurrWeek = 3)
BEGIN SET #date = #currdate + 7 END
IF (#CurrWeek = 4)
BEGIN SET #date = #currdate END
IF (#CurrWeek = 5)
BEGIN SET #date = #currdate - 7 END
END
IF (#Week = 5)
BEGIN
IF (#CurrWeek = 1)
BEGIN SET #date = #currdate + 28 END
IF (#CurrWeek = 2)
BEGIN SET #date = #currdate + 21 END
IF (#CurrWeek = 3)
BEGIN SET #date = #currdate + 14 END
IF (#CurrWeek = 4)
BEGIN SET #date = #currdate + 7 END
IF (#CurrWeek = 5)
BEGIN SET #date = #currdate END
END
Select CONVERT(date, DATEADD(wk, DATEDIFF(wk, 0, #date), - 1)) as startdate,
CONVERT(date, DATEADD(wk, DATEDIFF(wk, 0, #date), 5)) as enddate
RETURN

Answer 3

I modified code given by Valex to get the exact output as I required.
CREATE PROCEDURE dbo.SPReturnStartEndDateOfSpecifiedWeek
#Week int,
#P_startdate DateTime OUTPUT,
#P_enddate DateTime OUTPUT
AS
/* SET NOCOUNT ON */
with C(i) as
(
select CAST((DATEADD(mm, DATEDIFF(mm, 0, GETDATE()), 0)) as datetime) i
UNION ALL
select DATEADD (day,1,i) i from C
where DATEADD (day,1,i)<DATEADD(month,1,(DATEADD(mm, DATEDIFF(mm, 0, GETDATE()), 0)))
),
C1 as
(
select DATEPART(WEEK,i)-DATEPART(WEEK,(DATEADD(mm, DATEDIFF(mm, 0, GETDATE()), 0)))+1 WeekOfMonth,i from C
),
C2 as
(
select WeekOfMonth,min(i) StartDate, max(i) EndDate from C1 group by WeekOfMonth
)
Select #P_startdate = StartDate,
#P_enddate = EndDate
from C2
WHERE WeekOfMonth=#Week
RETURN

Answer 4

You can try this to get the start or end date for the week. Just provide a date for which you find the dates.
Logic is quite simple just get the start and end date of the week and then check if the start date is greater than the month date if so take the month date as the week start date else the start date of the week.
Fiddle a bit to get what you want
Here is the code:
DECLARE #date datetime
SET #date = '2013-01-30'
DECLARE #startdate datetime
DECLARE #enddate datetime
DECLARE #MonthStart datetime
Declare #MonthEnd datetime
SET #startdate = DATEADD(wk, DATEDIFF(wk, 6, #date), 6)
SET #enddate = DATEADD(dd,6, DATEADD(wk, DATEDIFF(wk, 6, #date), 6))
SET #monthStart = CONVERT(VARCHAR(25),DATEADD(dd,-(DAY(#date)-1),#date),101)
SET #MonthEnd =CONVERT(VARCHAR(25),DATEADD(dd,-(DAY(DATEADD(mm,1,#date))),DATEADD(mm,1,#date)),101)
--select #startdate wstart,#MonthStart monthstart,#enddate wend,#MonthEnd monthend
select
[date] = #date
,[week] = DATEPART(wk,#date)
,[WeekStartDate] = Case
WHEN #startdate <= #MonthStart then #MonthStart else #startdate
END
,[WeekEndDate] = Case
WHEN #enddate > #MonthEnd then #MonthEnd else #enddate
END
see here:
Fiddle