CASE statement SQL Between dates

Question

I am trying to design a CASE Statement in SQL Server for a report parameter. The report is presenting a timeframe against a set date. The expdate.

The parameter are sent in string format:

'All', '30', '31', '61', '91', '121', '150', '181+'

Trying to develop a CASE statement that will return:

WHERE expdate 
   CASE WHEN Timeframe = 'All' Then expdate  --All Dates
   CASE WHEN timeframe=30 THEN expdate between 0 and 30 --using datediff from today
   CASE WHEN timeframe=31 THEN expdate between 31 and 60 --using datediff 
   CASE WHEN timeframe=61 THEN expdate between 61 and 90 --using datediff 

...

If there is a better way to do this than a CASE statement in the WHERE clause, I am all ears, but that's how I have done it in the past.

Thanks

Answer 1

I would do it with an (AND) OR (AND) structure, like this:

WHERE (timeframe='All')
OR (timeframe='30' AND expdate between 0 and 30)
OR (timeframe='31' AND expdate between 31 and 60)
OR (...

Answer 2

Not use case when but OR and AND using make condition. I assume that expdate should be stored day. Like this

WHERE (Timeframe = 'All' AND expdate=expdate)  --All Dates
OR( timeframe=30 AND expdate between 0 and 30 )--using datediff from today
OR( timeframe=31 AND expdate between 31 and 60 )--using datediff 
OR (timeframe=61 AND expdate between 61 and 90) --using datediff