SQL Query to get data on Weekly basis in ASP.Net

Try This

declare @setting date;
set @setting = GETDATE()
--select @setting
;WITH WEEKS AS(
        SELECT  DATEADD(D, - DATEPART (WEEKDAY,@setting)+2, @setting) AS START_DATE, @setting  AS END_DATE, 1 AS WEEKNO
        UNION ALL
        SELECT  DATEADD(D,-7,START_DATE),DATEADD(D,-1,START_DATE), WEEKNO + 1
        FROM   weeks  WHERE WEEKNO < 1
)

or

refer

http://www.sqlfiddle.com/#!3/19086/44