我正在开发一个 Spring Boot 项目,使用 JPA 连接到我的数据库。我想进行本机查询来选择某些特定字段,但它不允许我这样做。例如,我只想获取客户的 id、名字、姓氏和电话号码,但这会引发错误,例如,
在此结果集中未找到列名 current_access_token。
这是我在 JPA 存储库中的查询代码,
@Query(value = "SELECT c.id, c.phone_number, c.firstname, c.lastname FROM tbl_customers c JOIN tbl_subscriptions s ON c.id = s.customer_id WHERE s.role = 'member' AND s.deleted_at IS NULL", nativeQuery = true)
List<Customer> findMemberByRole(String role);
这是我的Cutomer.java
@Getter
@Setter
@Accessors(chain=true)
@NoArgsConstructor
@AllArgsConstructor
@ToString
@Entity
@Table(name = "tbl_customers")
public class Customer implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(unique = true)
private Long id;
@Column(nullable = false, name = "phone_number")
private String phoneNumber;
private String firstname;
private String lastname;
@Column(name = "current_access_token")
private String currentAccessToken;
@Column(name = "consent_accepted")
private Boolean consentAccepted;
...
...
}
如何避免或忽略不需要的列?非常感谢您的帮助。
如果您确实只想从客户表中返回 4 列,那么您要在此处使用的签名是
List<Object[]>
:
@Query(value = "SELECT c.id, c.phone_number, c.firstname, c.lastname FROM tbl_customers c JOIN tbl_subscriptions s ON c.id = s.customer_id WHERE s.role = 'member' AND s.deleted_at IS NULL", nativeQuery = true)
List<Object[]> findMemberByRole(String role);
然后,在访问结果集时,您将使用类似以下内容:
List<Object[]> resultSet = findMemberByRole("admin");
for (Object[] rs : resultSet) {
Long id = (Long) rs[0];
String phoneNumber = (String) rs[1];
String firstName = (String) rs[2];
String lastName = (String) rs[3];
}
我找到了一种无需
Object[]
即可完成此操作的方法。假设您有一个 JPA 实体 MyEntity ,其中
作为 id 和内容的路径很大,比如说一个很大的 json,我们不想查询。这是我们能做的
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Entity
public class MyEntity {
@Id
String path;
String content;
}
@Query(value = "SELECT my.path, null as content FROM my_entity", nativeQuery = true)
Page<MyEntity> getPartialResults(Pageable pageable);