# query that divides month into "business weeks"

I need to break a report for date range of annual 09/01/YY - 08/31/YY+1) into weeks and months. Months is straightforward - Jan - Feb - Mar - April, etc.  The weeks are what I can't figure out - what I need is a function like so:

for a given annual period of time, divide results into regular calendar quarters, then calendar months (Q1 = Sept-Oct-Nov; Q2 = Dec-Jan-Feb; etc). Then break the calendar months into business weeks such that a business week is usually, but not always, Monday through Friday.  When the first week in a month doesn't start on a Monday, start that week on the first business day (Tues, wed, thurs, or Friday as applicable) and the week will have fewer than five days so that it ends on the first Friday. WHen the last week in a month doesn't end on Friday, end that week on the month's last business day and the week wil lhave fewer than five days.

End Result:

09/01/2010 - 08/31/2011 - annual period
09/01/2010 - 11/30/2010 = Q1
12/01/2010 - 02/27/2011 = Q2
03/01/2011 - 05/31/2011 = Q3
06/01/2011 - 08/31/2011 = Q4
09/01/2010 - 09/03/2010 = W1  (has only Wed - Friday)
09/06/2019 - 09/10/2010 = W2
09/13/2010 - 09/17/2010 = W3
09/17/2010 - 09/24/2010 = W4
09/27/2010 - 09/27/2010 = W5 (has only Monday - Thursday)
Week 1 - Week 5 belong to September 2010.

Assistance most welcome.
###### Who is Participating?

Commented:
OK, I would start be creating a "calendar table".  For example:

``````CREATE TABLE tblCalendar(Dt datetime, FiscalYear int, FiscalQuarter int,
FiscalMonth int, FiscalWeek int, Weekday int)

DECLARE @Dt datetime, @EndDt datetime, @FY int, @FM int, @FW int, @WD int,
@DayName varchar(20), @FQ int
SET @Dt = '2000-09-01'
SET @EndDt = '2020-08-31'
SET @FW = 0

WHILE @Dt <= @EndDt BEGIN

SET @FY = YEAR(@Dt) + CASE WHEN MONTH(@Dt) < 9 THEN 0 ELSE 1 END
SET @FM = MONTH(@Dt)
SET @DayName = LEFT(DATENAME(dw, @Dt), 2)
SET @FQ = CASE WHEN MONTH(@Dt) IN (9, 10, 11) THEN 1
WHEN MONTH(@Dt) IN (12, 1, 2) THEN 2
WHEN MONTH(@Dt) IN (3, 4, 5) THEN 3
ELSE 4 END

IF @DayName = 'Mo' BEGIN
SET @FW = @FW + 1
SET @WD = 1 END

IF @DayName = 'Tu' BEGIN
IF DAY(@Dt) = 1 SET @FW = @FW + 1
SET @WD = 2 END

IF @DayName = 'We' BEGIN
IF DAY(@Dt) = 1 SET @FW = @FW + 1
SET @WD = 3 END

IF @DayName = 'Th' BEGIN
IF DAY(@Dt) = 1 SET @FW = @FW + 1
SET @WD = 4 END

IF @DayName = 'Fr' BEGIN
IF DAY(@Dt) = 1 SET @FW = @FW + 1
SET @WD = 5 END

IF @DayName = 'Sa' SET @WD = 6

IF @DayName = 'Su' SET @WD = 7

INSERT INTO tblCalendar (Dt, FiscalYear, FiscalQuarter, FiscalMonth,
FiscalWeek, Weekday)
VALUES (@Dt, @FY, @FQ, @FM, @FW, @WD)

SET @Dt = DATEADD(day, 1, @Dt)
IF MONTH(@Dt) = 9 AND DAY(@Dt) = 1 SET @FW = 0

END
``````

With that in place, by joining just about any dated table to that calendar, you can generate your results for any given slice of time.
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Commented:
I think you meant that last row to be:

09/27/2010 - 09/30/2010 = W5 (has only Monday - Thursday)

Anyway, would Friday 1 Oct be the start of Week 1 (i.e., start the week numbering over with a change in month), or of Week 6 (i.e., continue the week numbering from the prior month)?

Also, what would we do about a month such as Jan 2011?  The 1st of the month is a Saturday; would we deem that the start of a week, and then that Monday, the 3rd, the start of another week?

I'm really not seeing the usefulness of breaking months up into individual weeks...
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Author Commented:
Hi Mathewspatrick:

- Correct.  09/27/2010 - 09/30/2010 = W5 (has only Monday - Thursday)
- Friday 1 Oct be the start of Week 6 (continue the week numbering from the prior month).
- For Jan 2011 the first business week of the month would be 1/3/11 through 1/7/11.
The weeks are divided up the way requested to accommodate performance measurements. Not the way I'd like to be doing it, believe me. I agree with you there. Craziness.
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Commented:
>>The weeks are divided up the way requested to accommodate performance measurements.

I'd be curious to see how those performance measurements accommodate the fact that a "week" can have anywhere from 1-5 days.

>>Craziness.

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Author Commented:
Thank you so very much!!!  There' s no doubt in my mind why you're a "Hall of Famer"!!!!  The proposed solution is exactly what I needed and I could never have solved this on my own. I very much appreciate not just the answer itself, but the fast reply, the excellent questions to make sure you understood what I needed, and the clarity in the responses.  You've made my whole week so much better!!!!  A++++
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Commented: