JPA Criteria query group by uses only the id

Question

This is a sample entity:

public class Account{

   @Id
   Long id
   Double remaining;
   @ManyToOne
   AccountType type
}

public class AccountType{
   @Id
   Long id;
   String name;
}  

Now i create a criteria query with Join as follwing :

CriteriaBuilder criteriaBuilder = getEntityManager().getCriteriaBuilder();
CriteriaQuery criteriaQuery = criteriaBuilder.createquery();
Root<Account> accountRoot = criteriaQuery.from(Account.class);
Join<Account, AccountType> typeJoin = accountRoot.join(Account_.type);

criteriaQuery.multiSelect(
    typeJoin,
    criteriaBuilder.sum(accountRoot.get(Account_.remaining))
);

criteriaQuery.groupBy(typeJoin);
Query query = getEntityManager().createQuery(criteriaQuery);
query.getResultList();  

The above code generate Sql command like following:

select accType.id, accType.name, sum(acc.remaining)
from account acc join accType on acc.accounttype_id = accType.id
group by accType.id  

Above code work in PosgreSQL but can't run in Oracle, because in it select accType.name that doesn't appear in the group by clause.

update :
I think my question isn't clear for you. My question isn't about PostgreSQL or Oracle behavior in group by. My question is this :
I use typeJoin in group by clause(this means I expect hibernate use all field of AccountType in group by), but why hibernate just use identity field on group by? if I will use just identity field in group by then I can use the following statement :

criteriaQuery.groupBy(typeJoin.get(AccountType_.id)) ;

Answer 1

JPA/Hibernate doesn't automatically include all entity properties in a group by clause, so you have to manually specify them:

CriteriaBuilder criteriaBuilder = getEntityManager().getCriteriaBuilder();
CriteriaQuery criteriaQuery = criteriaBuilder.createQuery();
Root<Account> accountRoot = criteriaQuery.from(Account.class);
Join<Account, AccountType> typeJoin = accountRoot.join(Account_.type);

criteriaQuery.multiSelect(
    typeJoin.get("id"),
    typeJoin.get("name"),
    criteriaBuilder.sum(accountRoot.get(Account_.remaining))
);

criteriaQuery.groupBy(typeJoin.get("id"), typeJoin.get("name"));
Query query = getEntityManager().createQuery(criteriaQuery);
query.getResultList();