JPA Criteria Query API and order by two columns

Question

I'm stuck with a simple problem; struggling how to invoke order by on a joined entity. Essentially I am trying to achieve the following with JPA Criteria:

select distinct d from Department d 
left join fetch d.children c 
left join fetch c.appointments a
where d.parent is null 
order by d.name, c.name

I have the following:

CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
CriteriaQuery<Department> c = cb.createQuery(Department.class);
Root<Department> root = c.from(Department.class);
Fetch<Department, Department> childrenFetch = root.fetch(
    Department_.children, JoinType.LEFT);
childrenFetch.fetch(Department_.appointments, JoinType.LEFT);

c.orderBy(cb.asc(root.get(Department_.name)));
c.distinct(true);
c.select(root);
c.where(cb.isNull(root.get(Department_.parent)));

How to achieve order by d.name, c.name with Criteria API? I tried with Expression, Path but didn't work. Any pointers will be greatly appreciated.

Answer 1

If you need to add couple of orders you can make something like (but for your query and different root objects)

CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Route> query = criteriaBuilder.createQuery(Route.class);
Root<Route> routeRoot = query.from(Route.class);
query.select(routeRoot);

List<Order> orderList = new ArrayList();
query.where(routeRoot.get("owner").in(user));

orderList.add(criteriaBuilder.desc(routeRoot.get("date")));
orderList.add(criteriaBuilder.desc(routeRoot.get("rating")));

query.orderBy(orderList);