getting the current cumulative COUNT() for each week - sql-server

Question

if I have following database records
dtAdded ItemName
...
2014-01-01 12:19:00 Aaasd
2014-01-02 01:19:00 Bbsadsad
2014-01-03 12:19:00 Ccasd
2014-01-04 12:19:00 Ddasd
2014-01-05 12:19:00 Eesadsad
2014-01-06 12:19:00 Ffsadsad
...
2014-02-11 12:19:00 Hasd
2014-02-12 02:19:00 Iasdsad
2014-02-12 12:12:00 Jasd
2014-02-12 04:19:00 Ksadsad
2014-02-12 08:29:00 Lsad
2014-02-13 0911:00 Masdsad
2014-02-13 11:19:00 Nsadsad
...
How to return the cumulative item total for every WEEK so it would return something like this (just the last 3-4weeks)
DATE Total
2014-01-26 30 <-- TOTAL ITEM PER THIS SUNDAY
2014-02-02 80 <-- TOTAL ITEM PER THIS SUNDAY
2014-02-09 120 <-- TOTAL ITEM PER THIS SUNDAY
2014-02-14 140 <-- THIS IS TODAY
Thank you

Answer 1

Well this is something... check if the days fall into the correct week, weekno from the US is different than from Europe for example...
SELECT DATEPART(year, dteAdded), DATEPART( wk, dtAdded), count(*)
FROM table
GROUP BY DATEPART(year, dteAdded), DATEPART( wk, dtAdded)
ORDER BY DATEPART(year, dteAdded), DATEPART( wk, dtAdded)

Answer 2

try this,
Declare #t table (dtAdded datetime, ItemName varchar(50))
insert into #t
select '2014-01-01 12:19:00','Aaasd' union all
select '2014-01-02 01:19:00','Bbsadsad' union all
select '2014-01-03 12:19:00','Ccasd' union all
select '2014-01-04 12:19:00','Ddasd' union all
select '2014-01-05 12:19:00','Eesadsad' union all
select '2014-01-06 12:19:00','Ffsadsad' union all
select '2014-02-11 12:19:00','Hasd' union all
select '2014-02-12 02:19:00','Iasdsad' union all
select '2014-02-12 12:12:00','Jasd' union all
select '2014-02-12 04:19:00','Ksadsad' union all
select '2014-02-12 08:29:0','Lsad' union all
select '2014-02-13 09:11:00','Masdsad' union all
select '2014-02-13 11:19:00','Nsadsad'
Declare #startdate date='2014-01-26'
Declare #enddate date
select #enddate= max(dtAdded) from #t
;with cte as
(
select #startdate dates
union all
select dateadd(day,7,dates)
from cte a where dates<=#enddate
)
Select dates ,
(select count(*) from #t where dtAdded<=a.dates)Total
from cte a

Answer 3

I have found the answer, here is the code with the actual table name (different from my question above)
WITH
CTE_Dates AS (
SELECT DISTINCT
cast(floor(cast(LastUpdateDate as float)) as datetime)
-DATEPART(dw,LastUpdateDate)+1 as BeginOfWeek,
cast(floor(cast(LastUpdateDate as float)) as datetime)
-DATEPART(dw,LastUpdateDate)+7 as EndOfWeek
FROM [linnworks_finaware].[dbo].[StockItems] si
INNER JOIN [linnworks_finaware].[dbo].[StockLevel] sl ON si.pkStockID = sl.[fkStockItemId]
WHERE sl.[Quantity] > 0
),
T AS (
SELECT
cast(floor(cast(LastUpdateDate as float)) as datetime)
-DATEPART(dw,LastUpdateDate)+1 as BeginOfWeek,
cast(floor(cast(LastUpdateDate as float)) as datetime)
-DATEPART(dw,LastUpdateDate)+7 as EndOfWeek
FROM [linnworks_finaware].[dbo].[StockItems] si
INNER JOIN [linnworks_finaware].[dbo].[StockLevel] sl ON si.pkStockID = sl.[fkStockItemId]
WHERE sl.[Quantity] > 0
)
SELECT
MIN(
CASE WHEN GETDATE()<CTE_Dates.EndOfWeek
THEN GETDATE()
ELSE CTE_Dates.EndOfWeek
END
) as EndOfWeek,
COUNT(*) AS Total
FROM CTE_Dates
INNER JOIN T
ON CTE_Dates.EndOfWeek >= T.EndOfWeek
GROUP BY CTE_Dates.EndOfWeek
ORDER BY EndOfWeek DESC