Question

我正在研究“你可能认识的人”功能。我有两张桌子：

USERS
ID
电子邮件
命名
等

友谊
USER_ID
friend_id

对于每个友谊我都会做两个记录。假设用户7和9成为朋友...我会在友谊表中创建user_id = 7，friend_id = 9和另一个user_id = 9，friend_id = 7的记录。

我如何制作一个sql查询，根据我朋友的朋友建议我可能知道的人？我也希望它是根据最共同的朋友订购的。

Answer 1

select u.id, u.email, u.name, u.etc
-- Get all my friends
from Friendships as f1
-- Get their friends
inner join Friendships as f2
    on f1.friend_id = f2.user_id
-- Get their friends User information
inner join Users as u
    on f2.friend_id = u.id
where f1.user_id = @userId

我会在哪里开始。

Answer 2

Select friend_id from friendships where user_id IN (select friendid from freindships where userid = <userid>)

考虑用户7和9是朋友。对于用户7，此查询将为您提供用户9的朋友列表。

Answer 3

select * from 
(select distinct friendsOfFriends.friends_id, count(1) as mutualfriends
  from FRIENDSHIPS friendsOfFriends
 inner join FRIENDSHIPS friends ON friends.friend_id = friendsOfFriends.user_id
  where friends.user_id = @myuserid
  group by friendsOfFriends.friends_id) t
order by mutualfriends desc

Answer 4

您可以使用以下查询;

<强>查询：

Select * from [USERS] U where id not in 
((select F.friend_id as id from [FRIENDSHIPS] f where f.user_id='" + Session["UserId"] + "' and f.Status=1)
union (select F.user_id as id from [FRIENDSHIPS] f where f.friend_id='" + Session["UserId"] + "' and f.Status=1)
union (select F.friend_id as id from [FRIENDSHIPS] f where f.user_id='" + Session["UserId"] + "' and f.Status=0)
union (select F.friend_id as id from [FRIENDSHIPS] f where f.user_id='" + Session["UserId"] + "' and f.Status=2))
and U.id !='" + Session["UserId"] + "'

注意：状态可能是＆＃34; 1 ＆＃34;，＆＃34; 0 ＆＃34;，＆＃34; 2 ＆＃34;作为默认参数。他们的意思是;

1 ：确认 0 ：尚未确认 2 ：拒绝

我通过这些参数编写了上面的查询代码。你的也可能是这样的。

放轻松！

“你可能知道的人”sql查询

4 个答案: