Using Min, Max and Count on HQL

问题

Does hibernate HQL queries support using select min, max, count and other sql functions?

like:

select min(p.age) from person p

Thanks

回答1:

Yes, min(), max() and count() are supported in HQL.

see aggregate functions in the Hibernate Doc.

回答2:

thats how I am using max in Hibernate :

public long getNextId(){
long appId;         
try{
            Session session = HibernateUtil.getAdmSessionFactory().getCurrentSession();
            Transaction t = session.beginTransaction();
            String sequel = "Select max(JAdmAppExemptionId) from JAdmAppExemption";
            Query q = session.createQuery(sequel);
            List currentSeq = q.list();
            if(currentSeq == null){
                return appId;
            }else{
            appId = (Long)currentSeq.get(0);
            return appId+1;
            }

        }catch(Exception exc){
            System.out.print("Unable to get latestID");
            exc.printStackTrace();

        }
        return 0;

    }

回答3:

Some aggregate functions are supported: look in the manual

来源：https://stackoverflow.com/questions/330918/using-min-max-and-count-on-hql