SQL - Generate bi-weekly end date on custom start date - sql

Question

I want to get a custom Fort Night period based on a given start date.
I have a table that looks like this:
IF OBJECT_ID('tempdb..#tbl1') IS NOT NULL DROP TABLE #tbl1
SET DATEFIRST 1
DECLARE #StartDateTime DATETIME
DECLARE #EndDateTime DATETIME
SET #StartDateTime = '2016-09-03'
SET #EndDateTime = '2017-01-28';
WITH DateRange(DateData) AS
(
SELECT #StartDateTime as Date
UNION ALL
SELECT DATEADD(d,1,DateData)
FROM DateRange
WHERE DateData < #EndDateTime
)
SELECT ROW_NUMBER() OVER(ORDER BY DateData ASC) As ROWNum,DateData AS Date1
into #tbl1
FROM DateRange
OPTION (MAXRECURSION 0)
GO
SELECT top 10 * FROM #tbl1
Date1
2016-09-09 00:00:00.000
2016-09-10 00:00:00.000
2016-09-11 00:00:00.000
2016-09-12 00:00:00.000
2016-09-13 00:00:00.000
2016-09-14 00:00:00.000
2016-09-15 00:00:00.000
2016-09-16 00:00:00.000
2016-09-17 00:00:00.000
2016-09-18 00:00:00.000
2016-09-19 00:00:00.000
2016-09-20 00:00:00.000
2016-09-21 00:00:00.000
2016-09-22 00:00:00.000
I want to say the the first date of my bi-weekly period is 2016-09-09 and it ends 2016-09-22. How do I get bi-weekly end date for each of those dates.
So I want it to look like
Date1 FortNightEndDate
2016-09-09 00:00:00.000 2016-09-22 00:00:00.000
2016-09-10 00:00:00.000 2016-09-22 00:00:00.000
2016-09-11 00:00:00.000 2016-09-22 00:00:00.000
2016-09-12 00:00:00.000 2016-09-22 00:00:00.000
2016-09-13 00:00:00.000 2016-09-22 00:00:00.000
2016-09-14 00:00:00.000 2016-09-22 00:00:00.000
2016-09-15 00:00:00.000 2016-09-22 00:00:00.000
2016-09-16 00:00:00.000 2016-09-22 00:00:00.000
2016-09-17 00:00:00.000 2016-09-22 00:00:00.000
2016-09-18 00:00:00.000 2016-09-22 00:00:00.000
2016-09-19 00:00:00.000 2016-09-22 00:00:00.000
2016-09-20 00:00:00.000 2016-09-22 00:00:00.000
2016-09-21 00:00:00.000 2016-09-22 00:00:00.000
2016-09-22 00:00:00.000 2016-09-22 00:00:00.000
I'm using SQL Server 2005.
ANSWER:
I was able to solve it using the following code. Essentially I just created 3 tables:
StartDates
EndDates
InbetweenDates
The Start/EndDates tables had just the start and End of my 2 week period and an ID (Row Number)
The InbetweenDates table had all the dates between the 2 dates and also had a ID column but instead of going up 1 every row, it went up 1 every 14 rows.
Then I just joined the 3 tables. Essentially, the Start/EndDates tables were lookup tables.
I got the RowNumber on every 14 days code from here.
-- BEtween Dates
IF OBJECT_ID('tempdb..#BetweenDates') IS NOT NULL DROP TABLE #BetweenDates
DECLARE #StartDateTime DATETIME
DECLARE #EndDateTime DATETIME
SET #StartDateTime = '2016-09-09'
SET #EndDateTime = '2017-04-30';
WITH DateRange(DateData) AS
(
SELECT #StartDateTime as Date
UNION ALL
SELECT DATEADD(d,1,DateData)
FROM DateRange
WHERE DateData < #EndDateTime
)
SELECT
DateData
into #BetweenDates
FROM DateRange
OPTION (MAXRECURSION 0)
GO
select
(case when convert(int, (ROW_NUMBER() OVER (Order by (select 0)) % 14))=0 then 0 else 1 end)
+ convert(int, (ROW_NUMBER() OVER (Order by (select 0)) / 14)) as ID
,DateData
INTO #BetweenDates_ID
from #BetweenDates
-- Start Dates
IF OBJECT_ID('tempdb..#StartDates') IS NOT NULL DROP TABLE #StartDates
DECLARE #StartDateTime DATETIME
DECLARE #EndDateTime DATETIME
SET #StartDateTime = '2016-09-09'
SET #EndDateTime = '2017-04-30';
WITH DateRange(DateData) AS
(
SELECT #StartDateTime as Date
UNION ALL
SELECT DATEADD(d,14,DateData)
FROM DateRange
WHERE DateData < #EndDateTime
)
SELECT ROW_NUMBER() OVER(ORDER BY DateData ASC) As ID,DateData
into #StartDates
FROM DateRange
OPTION (MAXRECURSION 0)
GO
-- End Dates
IF OBJECT_ID('tempdb..#EndDates') IS NOT NULL DROP TABLE #EndDates
DECLARE #StartDateTime DATETIME
DECLARE #EndDateTime DATETIME
SET #StartDateTime = '2016-09-22'
SET #EndDateTime = '2017-04-30';
WITH DateRange(DateData) AS
(
SELECT #StartDateTime as Date
UNION ALL
SELECT DATEADD(d,14,DateData)
FROM DateRange
WHERE DateData < #EndDateTime
)
SELECT ROW_NUMBER() OVER(ORDER BY DateData ASC) As ID,DateData
into #EndDates
FROM DateRange
OPTION (MAXRECURSION 0)
GO
--SELECT * FROM #StartDates
--SELECT * FROM #EndDates
--SELECT * FROM #BetweenDates_ID
SELECT
st.DateData AS StartDate
,ed.DateData AS EndDate
,bd.DateData AS BetweenDate
FROM
#StartDates st
JOIN
#EndDates ed
ON st.ID = ed.ID
LEFT JOIN
#BetweenDates_ID bd
ON st.ID = bd.ID

Answer 1

Try this:
SELECT Date1,
DATEADD(DD, -1, DATEADD(WW,2,Date1)) AS FortNightEndDate
FROM #tbl1