Hibernate HQL : หาค่า id

public int MaxIdenx() {
    int max = (Integer)session
        .createQuery("SELECT COALESCE(MAX(empId), 0) FROM Emp")
        .uniqueResult();

    return max + 1;
}

credit : http://stackoverflow.com/questions/13468276/how-to-use-syntax-of-mysql-such-as-ifnullmaxid-0-in-hibernate