I have a class Department which is mapped to table department.
class Department {
private long id;
private String name;
private Department parentDept;
private Set subDepts;
}
Department may has zero or one parent department and zero or more sub-departments which are also of Department type. I wanna get the following information, but don't know how to write such kind of HQL. Any help is appreciated !

(1) get all the departments which don't have any sub-department.
from hibernate.Department dept where count(elements(dept.subDepts))=0
(2) get all the departments which don't have parent department.
from hibernate.Department dept where dept.parentDept is null

The (1) hql doesn't work ! It reports "Syntax error or access violation, message from server: "You have an error in your SQL syntax. "

Hi,

Will this work for the first query ?

from hibernate.Department dept where dept.subDepts.size = 0

"size" property is a special property for collections

Clarence

Anybody can help ?
thanks !