I have three parameters on report , one is boolean and two are dates.Condition is, if user selects True from boolean parameter,it should display all data from table regardless of date ranges,whereas if user select False it should display data within date range.Problem is its not giving any result if user selects true.when i change the parameter type from boolean to String its giviing result.I have a limitation that i cannot change the parameter type from boolean to String.Below is the query for doing that:

select event_id,event_dt from event
where event_dt like decode('{?alldates}','True','%') or event_dt between
{?startdate} and {?endedate}

any suggestions ?