Input Control pass to Parameter '%' if null

[mgurtler]

I have an input control 'for_user' on the JasperServer that is setup as a non-mandatory single select query. I am passing that to a parameter which I'm using in the where clause of my report query in iReport. What I'd like to do is have the parameter be the SQL wildcard '%' if the user doesn't select anything from the input control dropdown so the report will return all results. My report query looks like this:

select from

If the user selects something from the 'for_user' input control dropdown the report returns results, if they don't and leave it blank the report returns nothing. I have the defaul value expression of the 'for_user' parameter in iReport set as "%" but it seems to be ignoring that. Does anyone have any advice? Thanks!

[butlerc]

Do this, create a 2nd parameter called  'for_userToken'

expression something like (you may need to tweek but you'll get the idea):  P${for_user} == null ? "%" : "table.mycolumn = " +  P${for_user}

you may need to use P${for_user}.length() == 0 depending on your column type as opposed to == null

then change your ireport sql to: WHERE $P!{for_userToken} note: the ! is vital