java - 如何使用 SUM 和 GROUP BY JPA Java 创建条件查询

Question

Here my changes base on Ish Answer:

public List<TopUpRAMSInfo> listadoTOPUP2(Date fechaI, Date fechaF) {
        List<TopUpRAMSInfo> lista;
        CriteriaQuery<TopUpRAMSInfo> data = cb.createQuery(TopUpRAMSInfo.class);
        Root<TopUpRAMS> c = data.from(TopUpRAMS.class);
        data.select(cb.construct(TopUpRAMSInfo.class,
                c.get("deviceId"),
                cb.sum(c.get("rechargeValue"))
        )
        );
        data.where(cb.greaterThanOrEqualTo(c.get("connectionTime"), fechaI),
                cb.lessThanOrEqualTo(c.get("connectionTime"), fechaF)
        );
        data.groupBy(c.get("deviceId"));
        TypedQuery<TopUpRAMSInfo> datos = emDAO.createQuery(data);
        lista = datos.getResultList();
        return lista;
    }

Now im having this error: java.lang.IllegalArgumentException: An exception occured looking on class: class ENTITY.TopUpRAMSInfo for constructor using selection criteria types as arguments. If this CriteriaQuery was not intended to be a constructor query please verify that the selection matches the return type.

----- ORIGINAL POST -----

我在执行此操作时遇到一些问题。这是我尝试构建的第一个真正的程序，我需要根据一个领域来总结另一个领域。

这是到目前为止我的代码(请注意，TopUpRAMS 是我的实体，emDAO 是我的实体管理器。

public List<TopUpRAMS> listadoTOPUP2(Date fechaI, Date fechaF) {
    List<TopUpRAMS> lista;

    CriteriaQuery<TopUpRAMS> data = cb.createQuery(TopUpRAMS.class);
    Root<TopUpRAMS> c = data.from(TopUpRAMS.class);

    data.multiselect(c.get("deviceId"), cb.sum(c.get("rechargeValue")));
    data.where(cb.greaterThanOrEqualTo(c.get("connectionTime"), fechaI));
    cb.and(cb.lessThanOrEqualTo(c.get("connectionTime"), fechaF));
    data.groupBy(c.get("deviceId"));

    TypedQuery<TopUpRAMS> datos = emDAO.createQuery(data);
    lista = datos.getResultList();
    return lista;
}

Answer 1

您构建 CriteriaQuery 的 WHERE 部分的方式存在问题。该表达式是唯一添加到 WHERE 子句的表达式:

cb.greaterThanOrEqualTo(c.get("connectionTime"), fechaI)

但不是这个:

cb.lessThanOrEqualTo(c.get("connectionTime"), fechaF)

任何 ff。可以解决这个问题:

1. 使用 cb.and():

   data.where(cb.and(
           cb.greaterThanOrEqualTo(c.get("connectionTime"), fechaI),
           cb.lessThanOrEqualTo(c.get("connectionTime"), fechaF)
       )
   );
   

2. CriteriaQuery.where() 可以接受可变数量的参数输入表达式，它们将使用连词(AND运算符(operator))。因此，我们不需要使用 cb.and():

   data.where(cb.greaterThanOrEqualTo(c.get("connectionTime"), fechaI),
       cb.lessThanOrEqualTo(c.get("connectionTime"), fechaF)
   );
   

您的 CriteriaQuery 中使用的类型也存在问题。您通过 data.multiselect() 进行 2 个字段的投影，这将无法转换为 TopUpRams 实体。

有 3 种方法可以进行多重选择/投影:

1. CriteriaQuery 类型将为 Object[]

   CriteriaQuery<Object[]> data = cb.createQuery(Object[].class);
   Root<TopUpRAMS> c = data.from(TopUpRAMS.class);
   data.multiselect(c.get("deviceId"), cb.sum(c.get("rechargeValue")));
   

2. CriteriaQuery 类型将为 Tuple

   CriteriaQuery<Tuple> data = cb.createTupleQuery();
   Root<TopUpRAMS> c = data.from(TopUpRAMS.class);
   data.multiselect(c.get("deviceId"), cb.sum(c.get("rechargeValue")));
   

3. 构造函数的使用

   CriteriaQuery<TopUpRAMSInfo> data = cb.createQuery(TopUpRAMSInfo.class);
   Root<TopUpRAMS> c = data.from(TopUpRAMS.class);
   data.select(cb.construct(TopUpRAMSInfo.class,
           c.get("deviceId"), 
           cb.sum(c.get("rechargeValue"))
       )
   );
   

   为此，您需要创建一个单独的类来表示类型您的查询结果(不必是实体):

   public class TopUpRAMSInfo {
       private Long deviceId; 
       private Double sumRechargeValue;
   
       public TopUpRAMSInfo(Long deviceId, Double sumRechargeValue) {
           this.deviceId = deviceId;
           this.sumRechargeValue = sumRechargeValue;
       }
       ...
   }
   

下面是对您的方法的修复示例:

public List<TopUpRAMSInfo> listadoTOPUP2(Date fechaI, Date fechaF) {

    List<TopUpRAMSInfo> lista;

    CriteriaQuery<TopUpRAMS> data = cb.createQuery(TopUpRAMSInfo.class);
    Root<TopUpRAMS> c = data.from(TopUpRAMS.class);
    data.select(cb.construct(TopUpRAMSInfo.class,
            c.get("deviceId"), 
            cb.sum(c.get("rechargeValue"))
        )
    );
    data.where(cb.greaterThanOrEqualTo(c.get("connectionTime"), fechaI),
        cb.lessThanOrEqualTo(c.get("connectionTime"), fechaF)
    );
    data.groupBy(c.get("deviceId"));

    TypedQuery<TopUpRAMSInfo> datos = emDAO.createQuery(data);
    lista = datos.getResultList();
    return lista;
}