如何通過相關實體

Question

的計數訂購我有兩個實體，文件和評論：

@Entity 
@Table(name = "FILE") 
@SuppressWarnings("serial") 
@XmlRootElement 
public class File implements Serializable { 

    (...) 
    private Set<Commentary> commentaries = new HashSet<Commentary>(); 

    (...) 
    @OneToMany(mappedBy = "file") 
    public Set<Commentary> getCommentaries() { 
     return commentaries; 
    } 
} 

@Entity 
@Table(name = "COMMENTARY") 
@SuppressWarnings("serial") 
public class Commentary implements Serializable { 

(...) 
private File file; 

(...) 
@ManyToOne 
@JoinColumn(name = "FILE_ID") 
public File getFile() { 
    return file; 
} 

我想打一個HQL查詢來獲取文件，評註的每一個具有關聯的數量進行排序。我試過了：

SELECT f FROM FILE f WHERE f.name LIKE '%example%' ORDER BY COUNT(f.commentaries) 

沒有運氣。我如何正確使用HQL來做到這一點？

Answer 1

我已經找到了答案。正確的HQL查詢是：

SELECT f FROM FILE f WHERE f.name LIKE '%example%' ORDER BY size(f.commentaries) 

Answer 2

試試這個

SELECT f FROM FILE f WHERE f.name LIKE '%example%' ORDER BY COUNT(commentaries)