HQL如何查询return实体？

Question

您好，我正在努力让这个查询成功执行。我有这 2 个实体，并且都有它们适当的 getter 和 setter。

@Entity
@Table(name="customer")
public class Customer {

    @Id
    @Column(name="Customer_Code")
    private String customer_Code;

    @Column(name="Customer_Name")
    private String customer_Name;
}


 @Entity
@Table(name="project")
public class Project {

    @Id
    @Column(name="Project_Code")
    public String project_Code;

    @Column(name="Project_Customer")
    public String project_Customer;

    @Column(name="Project_Description")
    public String project_Description;

    @Column(name="Project_Pastel_Prefix")
    public String project_Pastel_Prefix;

    @Column(name="Project_Name")
    public String project_Name;
}

十这是我的控制器方法：

// need to inject the session factory
    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public List<Customer> getCustomers() {

        // get the current hibernate sessio
    Session currentSession = sessionFactory.getCurrentSession();

    // create a query  ... sort by last name
    Query<Customer> theQuery = 
            currentSession.createQuery("Query goes here",
                                        Customer.class);

    // execute query and get result list
    List<Customer> customers = theQuery.getResultList();

        // return the results       
        return customers;
    }

我正在尝试执行此查询“SELECT DISTINCT Customer.* FROM Customer, Project WHERE Customer_Code=Project_Customer ORDER BY Customer_Name "

我试过以下方法：

"select 将 Customer 与 Customer 区别为 cus，Project 为 pro where cus.customer_code = pro.project_Customer 按 cus.customer_Name 排序"
"select 不同于客户 cus.customer_Code、cus.customer_Name 作为客户，项目作为专业人士，其中 cus.customer_code = pro.project_Customer 按 cus.customer_Name 排序
"来自客户客户，项目专家，其中 cus.customer_Code = pro.project_Customer 按 cus.customer_Name 排序

但没有任何效果。我通常会收到错误 无法使用请求的结果类型 [com.timesheet_Webservice.entity.Customer]

为具有多个 return 的查询创建类型化查询

这似乎意味着我没有像使用简单的 "from Customer" 查询那样获取客户实体的实例。如果是这样，我如何 return 客户实体？如果不是那我做错了什么？

Answer 1

当您执行 Customer.* 时，查询应该是 select customer_Code 和 customer_Name 这两个 String 对象。但是您期待一个 Customer 实体作为结果。

查询 select 一个像这样的 Customer 对象。

select distinct cus from Customer as cus, Project as pro where cus.customer_code = pro.project_Customer order by cus.customer_Name

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