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       JPQLÓï¾ä£ºhibernateµÄHQLÓï¾äÒ»Ñù¡£
¼òµ¥²éѯ:
  Query query = em.createQuery("SELECT c from Customer c");
  return query.getResultList();
ÃüÃû²éѯ
  @Entity
  @NamedQuery(name = "findCustomerByName",
              query = "SELECT c from Customer c
                                WHERE c.name
                                LIKE :name ")
       ·ÖÒ³:
  query = em.createNamedQuery("findCustomerByName");
  query.setParameter("name", "t,om");
  query.setMaxResults(10);
  query.setFirstResult(3);
  List customers = query.getResultList();
ÉèÖòÎÊý:
  SELECT o from Order i WHERE i.orderNo = ?1
  query.setParameter(1, 100.00);
  SELECT o from Order i WHERE o.price = :price
  query.setParameter("price", 100.00);
µ¥¸öʵÌå¼ìË÷
  query.getSingleResult();
²éѯ¼¯ºÏ:
  WHERE c.orders IS EMPTY
  WHERE CONCAT(c.fname, c.lname) = 't,om'
  SELECT c.id, c.name from Customer c
¶à̬²éѯ
  SELECT c from Customer c WHERE c.name LIKE :name
·Ö×é
  SELECT o.customer, COUNT(o.id) from Order o
                                     GROUP BY o.customer
ÅÅÐò
  order by
×Ó²éѯ
  SELECT o from Order I WHERE o.customer