I have one problem. Why below sql commnad just can run in Oracle. When i run it in informix DB, it has syntax error??

select interval, count(*) from
select *
from (select trunc((DC.p_date - (
select min(DC.p_date) from DC))*48) as interval from DC)
group by interval order by interval

How to change and let it can execute in informix DB???

Thank a lot