Question

我有一个朋友表，可以跟踪我的数据库中的关系用户之间的连接是双向的。我正在为一个可能的朋友＆＃34;功能，我需要向所有朋友的朋友展示谁不是我的朋友，并通过总共普通朋友的降序对他们进行排序

结构表＆＃34; FRIENDS＆＃34;：

 user_id    |    friend_id    
    1               2               
    2               1                
    1               3               
    3               1               
    3               4               
    4               3               
    2               6   
    6               2
    3               6
    6               3

例如，user_id = 1的可能朋友，这是6和4.

我试图得到这样的东西：

 user_id    |    Possible id    |    id common friends      |    Total common friends    
                 (friend_id)
    1               6                       2                           2
    1               6                       3                           2
    1               4                       3                           1

我该如何进行此类查询？

谢谢你

Answer 1

试试这个：

SELECT f1.user_id, 
       f2.friend_id as "Possible id (friend_id)", 
       f1.friend_id as "id common friends",
       f3.total as "Total common friends"
FROM friends f1
INNER JOIN friends f2 on f1.friend_id = f2.user_id and f1.user_id <> f2.friend_id
INNER JOIN (
    SELECT fa.user_id, 
           fb.friend_id, 
           count(fb.friend_id) as total 
    FROM friends fa
    INNER JOIN friends fb on fa.friend_id = fb.user_id and fa.user_id <> fb.friend_id
    GROUP BY fa.user_id, fb.friend_id
) f3 on f3.user_id = f1.user_id and f3.friend_id = f2.friend_id

Mysql查询搜索可能的朋友

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