asked on

Best practice on "CASE" script

The script i have works but very long and i have run into a "CASE" statement limit so i can not go as far back in history as i would like. Here is a example of what i am currently using.

SELECT ITEM_NO, 
	CASE 
		WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 7 THEN 'Week_01' 
		WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 14 THEN 'Week_02' 
		WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 21 THEN 'Week_03' 
		WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 28 THEN 'Week_04' 
		WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 35 THEN 'Week_05'
		WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 42 THEN 'Week_06'
		WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 49 THEN 'Week_07' 
                WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 56 THEN 'Week_08' 
                WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 63 THEN 'Week_09' 
                WHEN datediff(DD, [BUS_DAT], GETDATE()) <= 70 THEN 'Week_10' 
		ELSE NULL 
	END AS SALE_WEEK, QTY_SOLD
FROM dbo.PS_TKT_HIST_LIN

Open in new window

What this is doing is labeling each line according to what week the sale falls in to by counting back 7 day from the current date to create week one and so on and so forth. I'm looking to a way to not use so many when clauses and i can look back 3 or 4 years if i want.

Thank you for your help and let me know if you have any further questions.

ASKER CERTIFIED SOLUTION

Brian Crowe

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

David Todd

Hi,

select dateadd( week, (datediff( week, 0, getdate()), 0 ) should give the date at the start of the week.

You may need to change the 0 to -1 or something as the base datetime. Depends on what you want as the starting day for the week.

HTH
David

Best practice on &quot;CASE&quot; script

Best practice on "CASE" script