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我已经为按特定列分组的存储库方法编写了本机查询。

我不能分组，id因为这会破坏分组。

      @Query(nativeQuery = true, value = "SELECT description, model_year, take_rate, number " +
          "FROM foo f " +
          "INNER JOIN bar b " +
          "ON b.cycle_plan_code = b.cycle_plan_code " +
          "WHERE b.programme = :programme " +
          "AND b.build_event = :buildEvent " +
          "AND f.vehicle_line = :vehicleLine " +
          "GROUP BY description, take_rate, model_year, number")
  List<FooEntity> findAllFooByBar(@Param("vehicleLine") String vehicleLine, @Param("programme") String programme,
                                          @Param("buildEvent") String buildEvent);

我的实体有一个@Id专栏和其他一些

@Table(name = "foos")
public class FooEntity {

  @Id
  private Long id;

  @Column(name = "cycle_plan_code")
  private String cyclePlanCode;

  @Column(name = "model_year")
  private String year;

  @Column(name = "vehicle_line", nullable = true)
  private String vehicleLine;

  @Column(name = "number")
  private Integer number;

  @Column(name = "description")
  private String description;

  @Column(name = "take_rate")
  private double takeRate;

}

访问存储库方法时，它会引发休眠

o.h.engine.jdbc.spi.SqlExceptionHelper   : Column 'id' not found.

我试图通过将其添加到 select 子句来破解它

SELECT 0 as id

这会取得进展，但是它会抱怨查询没有返回实体的其他列vehicle_line，model_year 我必须将它们全部添加到查询中才能使其正常工作。

我尝试了nullable = true注释中的标志，但这不允许我从 select 子句中省略列。

如何返回仅返回一些我感兴趣的列的实体？

4

1 回答 1

1

尝试使用 Projections：使用所需字段的 getter 声明一个接口：

public interface SubFooEntity{
String getDescription();
String getModelYear();
Double getTakeRate();
Integers getNumber(); 
}

将存储库方法更改为以下：

 @Query("SELECT description, modelYear, takeRate, number " +
      "FROM foo f " +
      "INNER JOIN bar b " +
      "ON b.cyclePlanCode = b.cyclePlanCode " +
      "WHERE b.programme = :programme " +
      "AND b.build_event = :buildEvent " +
      "AND f.vehicle_line = :vehicleLine " +
      "GROUP BY description, takeRate, modelYear, number")


List<SubFooEntity> findAllFooByBar(@Param("vehicleLine") String vehicleLine, @Param("programme") String programme,
                                          @Param("buildEvent") String buildEvent);

更多信息在这里：https ://docs.spring.io/spring-data/jpa/docs/current/reference/html/#projections

于 2018-11-29T17:24:59.087 回答