how to create jpql query to get Entity with no associated parent

Question

I have a unidirectional relationship between an Employee and his Location .The Location is unaware of Employee.

emp1-----------> loc1
emp2------------> loc1
emp3------------> loc3

Using JPA, I mapped this as follows

@Entity
class Employee{
   ...
   @ManyToOne
   Location location;
}
@Entity
class Location{
   ...
   int roomNumber;
   String aptName;
   String street;
   String city;
}

Is it possible to make a jpql query to get a list of all Location objects that have no Employee associated with it.

Answer 1

I think this will work.

select l from Location l where l not in (select e.location from Employee e)