APEX

I am trying to dynamically change what a report displays based on what is selected in a radio group.

   if :p33_RG = 'Daily' then
        select project_name, to_char(date_sys, 'MM/DD/YYYY') as Day,      
    sum(BATCH.RECORDS_NUMBER) as Count_of_Documents
    from BATCH
    where date_sys between :P33_START_DATE and :P33_END_DATE
    group by project_name, to_char(date_sys, 'MM/DD/YYYY');
   else if
    :p33_RG = 'Weekly' then
    select project_name, to_char(TRUNC(date_sys, 'IW'), 'MM/DD/YYYY') as WEEK, 
    sum(BATCH.RECORDS_NUMBER) as Count_of_Documents
    from BATCH
    where date_sys between :P33_START_DATE and :P33_END_DATE
    group by project_name, TRUNC(date_sys, 'IW');
   end if;

however I am getting multiple errors when I try to run this. Any suggestions on how I can change the script?