Question

在这个简化的场景中使用HQL：

String query =  "SELECT new CustomUser(" +
                "user.userID AS id," +
                "user.username AS username)" +
                "FROM User AS user" +
                " LEFT JOIN user.friends as friend " +
                " where user.username like (:query)" +
                " OR " +
                " friend.username like (:query) ";

这只回馈那些至少有一个朋友的用户，但我想让用户接受一个条件，除了和朋友在一起之外。

由于域要求而使用动态实例化
我注意到，如果联接表上没有条件（ friend.username like（：query）），它会给所有用户，有或有朋友。

这些是我的表格：

用户

@Id...
protected Integer userID;

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

@OneToMany(mappedBy = "user", cascade = CascadeType.REMOVE)
private List<Friend> friends;

朋友

    @Id
    private Integer friendID;

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

    @ManyToOne(cascade = CascadeType.DETACH)
    @JoinColumn(name="userid")
    private User user;

注意：它的工作方式与原生SQL上的预期相同

Answer 1

您可以尝试此查询 String query = "SELECT new CustomUser(" + "user.userID AS id," + "user.username AS username)" + "FROM User AS user" + " LEFT OUTER JOIN user.friends as friend " + " where user.username like (:query)" + " OR " + " friend.username like (:query) ";

使用LEFT JOIN的HQL查询和WHERE不给出结果

1 个答案: