Problems creating a Query Item in Cognos 8 Framework Manager

I have two Query Subjects: TICKETS (with columns id_ticket and insertDate) and HOLIDAYS(with only one column: hDate).
I must create another column in query subject TICKETS: Holidays_count that counts the number of days of HOLIDAYS with HOLIDAYS.hDate > TICKETS.insertDate

Using SQL it could be:

select T.id_ticket,
T.insertDate,
(Select count(1) from HOLIDAYS H where H.hDate > T.insertDate) Holidays_count
from TICKETS T


I think I must use 'count' expression, but I don´t know how to apply the filter: H.hDate > T.insertDate in the FM Expression Editor.

Thanks in advance.