Microsoft SQL Calculating Backlog - sql-server

Question

I would like to calculate the backlog for every week in the past month. Date format is in (MM/DD/YY)
| mutation | issued_date | queryno_i | status |
-----------------------------------------------
01/05/14 12/31/13 321 OPEN
01/02/14 08/01/13 323 CLOSED
01/01/14 06/06/13 123 OPEN
01/01/14 01/01/14 1240 CLOSED
01/02/14 01/01/14 1233 OPEN
01/03/14 01/03/14 200 CLOSED
01/05/14 01/04/14 300 OPEN
01/06/14 01/05/14 231 OPEN
01/07/14 01/06/14 232 CLOSED
01/09/14 01/10/14 332 OPEN
01/11/14 01/11/14 224 CLOSED
01/15/14 01/14/14 225 CLOSED
01/16/14 01/15/14 223 OPEN
I want my result set to look like this:
WeekNum | Opened | Closed | Total Open
--------------------------------------
1 4 3 4 <= (2-4)+ data in week 2 so (2-4)+(1-2)+7
2 4 2 6 <= (1-2)+7
3 2 1 7 <= total count
My Code is below however I am not sure how to query the last part. I am not even sure if this is possible or not.
WITH
issued_queries AS
(
SELECT DATEPART(wk, issued_date) AS 'week_number'
,COUNT(queryno_i) AS 'opened'
FROM t.tech_query
WHERE DATEADD(D,-12,issued_date) > GETDATE()-40
GROUP BY DATEPART(wk, issued_date)
),
closed_queries AS
(
SELECT DATEPART(wk, mutation) AS 'week_number'
,COUNT(queryno_i) AS 'closed'
FROM t.tech_query
WHERE status=3 AND DATEADD(D,-12,issued_date) > GETDATE()-40
GROUP BY DATEPART(wk, mutation)
),
total as
(
SELECT COUNT(*) AS 'total'
FROM t.tech_query
WHERE status!='3'
)
SELECT issued_queries.week_number
, issued_queries.opened
, closed_queries.closed
FROM issued_queries JOIN closed_queries
ON (issued_queries.week_number = closed_queries.week_number)
ORDER BY week_number

Answer 1

Backlog for every week in the past month.
I've taken this to mean last 4 weeks, as that appears to be what you are doing.
Assuming "mutation" represents the date a record was updated (maybe set to closed).
So first, I generate a list of dates, so that way there will be an answer for week number X even if there are no new/closed records.
declare #SundayJustGone datetime
-- We need to get rid of the time component, done through convert.
set #SundayJustGone = convert(date, dateadd(d, 1-DATEPART(dw, getdate()), getdate()))
-- If earlier than sql 2008, can get rid of time component through: set #SundayJustGone = SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, #SundayJustGone))
;with
Last4Weeks as
(
-- Get the sunday of the week just gone.
select #SundayJustGone as SundayDate -- Sunday just gone
union all
select dateadd(d, -7, SundayDate) -- Get the previous Sunday
from Last4Weeks
where dateadd(d, -7, SundayDate) > dateadd(Wk, -4, #SundayJustGone) -- where the new date is not more than 4 weeks old
)
select A.SundayDate,
DATEPART(wk, DateAdd(d, -1, A.SundayDate)) as Week_Number, -- SQL considers Sunday the first day of the week, so we need to move it back 1 day to get the right week
(select count(*)
from t.tech_query
where issued_date between DateAdd(d, -6, A.SundayDate) and A.SundayDate -- Was issued this week. (between monday - sunday)
) as Opened,
(select count(*)
from t.tech_query
where status = 3 -- where it is closed
and mutation between DateAdd(d, -6, A.SundayDate) and A.SundayDate -- and the mutation was this week. (between monday - sunday)
) as Closed,
(select count(*)
from t.tech_query
where (status != 3 or datediff(d, mutation, A.SundayDate) < 0 ) -- Is still open, or was closed after this week.
and datediff(d, issued_date, A.SundayDate) >= 0 -- and it was issued on or before the sunday.
) as TotalOpen
from Last4Weeks as A
hopefully this helps.
the results are different to yours, as I assume Monday is the first day of the week. To change start of week back to sunday, saturday needs to be considered end of week, so, change the set #SundayJustGone = convert(date, dateadd(d, 1-DATEPART(dw, getdate()), getdate())) to set #SundayJustGone = convert(date, dateadd(d, -DATEPART(dw, getdate()), getdate())) (1 removed)