how to get the start and end dates of all weeks be

问题:

I need to get all week start and end dates(weeks) between two dates and then run a query returning the number of records inserted in each of those weeks.

declare @sDate datetime,
        @eDate datetime;

select  @sDate = '2013-02-25',
        @eDate = '2013-03-25';

--query to get all weeks between sDate and eDate

--query to return number of items inserted in each of the weeks returned



WEEK                  NoOfItems
-----------------------------------------
2013-02-25            5
2013-03-4             2
2013-03-11            7

回答1:

You can use a recursive CTE to generate the list of dates:

;with cte as
(
  select @sDate StartDate, 
    DATEADD(wk, DATEDIFF(wk, 0, @sDate), 6) EndDate
  union all
  select dateadd(ww, 1, StartDate),
    dateadd(ww, 1, EndDate)
  from cte
  where dateadd(ww, 1, StartDate)<=  @eDate
)
select *
from cte

See SQL Fiddle with Demo.

Then you can join this to your table, to return the additional details.