I have a Simple class hierarchy (with InheritanceType.JOINED strategy):
C extends B extends A

In a select using jpql I want to retrieve only the "A part" of my data.

I try the following query but it always returns complete C object

select object FROM A object WHERE TYPE(object) = A

I also try the TYPE function but it act as a filter instead an filter the database to return only A object.
In my case it return 0record because all my objects in the table are of C type.

The generated sql contains this kind of "CASE" instruction:
case when C.databaseId is not null then 2 when B.databaseId is not null then 1 when A.databaseId is not null then 0 end=0

Does jpa support this kind of functionnality?
Am I doing something wrong?