Hi ,
I have a filter on a column called book_date . The filter looks like [Book Date] in ?Accounting_Period?
This works fine and shows the prompt as a multiselect prompt . But when I try to add a case statement which looks like below , the prompt changes to single select radio button instead of the check box I have . 
[Book Date] in
(Case when ?Filter On? in ('Accounting Period')
then
?Accounting Period?
else
{sysdate}
end)
The above filter makes the prompt a radio button single select . Does anyone know what is the Issue in the above filter?  I am using Cognos 10 Reportstudio.
Thanks,
			
			
			
				The problem is that you have ?Accounting_Period? as the outcome of a "then" in the case statement. How could that possibly work if multiple values were selected from the prompt?
Is the expression intended as a filter? If so, then case logic is not your friend. Maybe the below is what you're after?
(
  [Book Date] in ?Accounting_Period? 
  and 
  ?Filter On? in ('Accounting Period')
)
or
(
  [Book Date] not in ?Accounting_Period? 
  and 
  [Book Date] in {sysdate}
)