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using T-SQL generate a weekly time frame table

Hi, experts

I would like to generate a weekly time frame table which consists of 2 columns (start_day & end_day). start_day is ALWAYS Sunday, end_day is ALWAYS Saturday

The input for start_day is ALWAYS Sunday as well, but the input of end_day might not necessary be Saturday.

In the case of input of end_day is not Saturday, the query will automatically figure out the Saturday for that week.

Here is an example:
giving the start_day "2011-02-06" (it is Sunday) and end_day "2011-02-28" (it is not Saturday)
my T-SQL will generate a result like below

Start_Day End_Day
2011-02-06 2011-02-12
2011-02-13 2011-02-19
2011-02-20 2011-02-26
2011-02-27 2011-03-05 --> 3/5/2011 is the Saturday of the giving end_day ("2011-02-28"

Is there a good way to do this? thank you in advance.

SOLUTION

mcv22

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HainKurt

create a table numbers (n int) put 0,1,..,9

create view v_nn as
select n1.n*10+n2.n as n from numbers n1, numbers n2

this view will give you numbers from n=0 to 99

now

select * from v_nn where n between DATEPART(ww,@startday) and DATEPART(ww,@endday)

will give you week numbers

then

declare @startday datetime
declare @endday datetime

set @startday = '2011-02-06'
set @endday = '2011-02-28'

select n WEEK_NO, 
@startday - DATEPART(w, @startday)+1+7*(n-DATEPART(ww,@startday)) WEEK_START,
@startday - DATEPART(w, @startday)+1+7*(n+1-DATEPART(ww,@startday)) WEEK_END
from v_nn where n between DATEPART(ww,@startday) and DATEPART(ww,@endday)

7	2011-02-06 00:00:00.000	2011-02-13 00:00:00.000
8	2011-02-13 00:00:00.000	2011-02-20 00:00:00.000
9	2011-02-20 00:00:00.000	2011-02-27 00:00:00.000
10	2011-02-27 00:00:00.000	2011-03-06 00:00:00.000

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HainKurt

and this one:

select n WEEK_NO, 
@startday - DATEPART(w, @startday)+1+7*(n-DATEPART(ww,@startday)) WEEK_START,
@startday - DATEPART(w, @startday)+1+7*(n+1-DATEPART(ww,@startday))-1 WEEK_END
from v_nn where n between DATEPART(ww,@startday) and DATEPART(ww,@endday)

7	2011-02-06 00:00:00.000	2011-02-12 00:00:00.000
8	2011-02-13 00:00:00.000	2011-02-19 00:00:00.000
9	2011-02-20 00:00:00.000	2011-02-26 00:00:00.000
10	2011-02-27 00:00:00.000	2011-03-05 00:00:00.000

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HainKurt

and this

select n WEEK_NO, 
cast(@startday - DATEPART(w, @startday)+1+7*(n-DATEPART(ww,@startday)) as date) WEEK_START,
cast(@startday - DATEPART(w, @startday)+1+7*(n+1-DATEPART(ww,@startday))-1 as date) WEEK_END
from v_nn where n between DATEPART(ww,@startday) and DATEPART(ww,@endday)

7	2011-02-06	2011-02-12
8	2011-02-13	2011-02-19
9	2011-02-20	2011-02-26
10	2011-02-27	2011-03-05

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HainKurt

this works as long as dates are in the same year :)

HainKurt

this works if they are in different years:

declare @startday datetime
declare @endday datetime

set @startday = '2011-02-06'
set @endday = '2012-02-28'

select n+1 WEEK_NO, 
cast(@startday + 7*n as date) WEEK_START,
cast(@startday + 7*n+6 as date) WEEK_END
from v_nnn where n <= DATEDIFF(ww,@startday,@endday)
order by n

WEEK_NO	WEEK_START	WEEK_END
1	2011-02-06	2011-02-12
2	2011-02-13	2011-02-19
...
55	2012-02-19	2012-02-25
56	2012-02-26	2012-03-03

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SOLUTION

HainKurt

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