از روشهای زیر میتونید استفاده کنید :
1 :
from t1 in db.Appointments
where date1 >= t1.AppointmentStart
where date2 <= t1.AppointmentEnd
select t1;
2 :
from t1 in db.Appointments
where date2 > t1.AppointmentStart
where date1 < t1.AppointmentEnd
select t1;
3 :
var query = (from a in announcements
where (a.Begins <= RightNow) && (a.Expires >= RightNow)
select a).ToList();