错误：列“this_.created_time”必须出现在GROUP BY子句中或用于聚合函数

Question

当我使用hibernate的条件执行查询时遇到问题。生成的SQL很简单：

/* criteria query */ 
select 
    count(*) as y0_ 
from 
    cx_vss_video this_ 
where 
    this_.uploader_id=? 
order by 
    this_.created_time asc 

它抱怨错误：

Caused by: org.postgresql.util.PSQLException: ERROR: column "this_.created_time" must appear in the GROUP BY clause or be used in an aggregate function 
    Position: 105 
     at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2157) 

有一个存在samilar问题here。但其答案似乎非常复杂，并且不合理。那么还有其他解决方案

我的实体类：

@Entity 
@Table(name = "cx_vss_video") 
public class Video { 

    public enum TranscodingStatus { 
     NOT_START, TRANSCODING, SUCCESS, ERROR, CANCELED; 
    } 

    @Id 
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "cx_vss_video_seq") 
    @SequenceGenerator(name = "cx_vss_video_seq", sequenceName = "cx_vss_video_seq") 
    private Long id; 

    @Column(name = "uploader_name", nullable = false) 
    private String uploaderName; 

    @Column(name = "file_name") 
    @NaturalId 
    private String fileName; 

    @Column(name = "created_time") 
    private Date createdTime = new Date(); 

    @Column(name = "transcoding_status") 
    @Enumerated(EnumType.STRING) 
    private TranscodingStatus transcodingStatus = TranscodingStatus.TRANSCODING; 
} 

我可以file_name normaly秩序，而且当created_time下令没有运气。我很困惑问题出现在哪里？当我使用H2时，问题也会出现。

编辑 我终于通过删除命令参数解决了问题，它现在可以工作。

CriteriaImpl criteriaImpl = criteria instanceof CriteriaImpl ? (CriteriaImpl) criteria : null; 
    if (criteriaImpl != null) { 
    Iterator<OrderEntry> it = criteriaImpl.iterateOrderings(); 
    while (it.hasNext()) { 
     it.next(); 
     it.remove(); 
    } 
    criteria.setProjection(Projections.rowCount()); 
    totalResults = (long) criteria.uniqueResult(); 
    } 

Answer 1

您需要查询的聚合函数。因此，它应该是这样的：

select count(*) as y0_ 
from cx_vss_video this_ 
where this_.uploader_id = ? 
group by ?? 
order by max(this_.created_time) asc; 

也就是说，你需要一个group by并修复order by。

为什么？那么，你的原始查询 - 没有group by - 是一个返回一行的聚合查询。用一行命令结果集没有意义。所以，我假设你想要聚合的东西，因此??。然后，您可以通过聚合列或聚合函数进行排序。