如何编写HQL以查询多对多？

Question

我有用户模型，系统允许用户互相关注。 因此，我在用户模型中放置了两个列表，如下所示：

@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(name = "t_user_t_followingUser", joinColumns = { @JoinColumn(name = "user_id") }, inverseJoinColumns = { @JoinColumn(name = "followingUser_id") })
public List<User> getFollowingUsers() {
    return followingUsers;
}

public void setFollowingUsers(List<User> followingUsers) {
    this.followingUsers = followingUsers;
}

@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(name = "t_user_t_followedUser", joinColumns = { @JoinColumn(name = "user_id") }, inverseJoinColumns = { @JoinColumn(name = "followedUser_id") })
public List<User> getFollowedUsers() {
    return followedUsers;
}

public void setFollowedUsers(List<User> followedUsers) {
    this.followedUsers = followedUsers;
}

现在，我想获得用户u的全部关注者。 如何编写HQL？

ps：many2many可能不合适，对设计有什么建议吗？

提前致谢。

Answer 1

尝试SELECT COUNT(fu) FROM User AS u INNER JOIN u.followedUsers AS fu;