MySQL：用户在线状态[帮助]

Question

我已经为朋友设置了用户在线状态

SELECT * FROM users 
WHERE
    (id_user IN 
        (SELECT CASE 
            WHEN friend_one = '{$id}' 
                THEN friend_two 
            WHEN friend_two = '{$id}' 
                THEN friend_one 
            END 
        FROM friends 
        WHERE status = '1')
    ) AND (status = '1' OR ($date - last_login) <= 300)

它有效，这个mysql只显示朋友登录状态列表。

但问题是当我尝试创建另一个用户登录状态时，它只显示另一个登录但不在我们的朋友列表中的人的列表。

SELECT * FROM users 
WHERE
    (id_user NOT IN 
        (SELECT CASE 
            WHEN friend_one = '{$id}' 
                THEN friend_two 
            WHEN friend_two = '{$id}' 
                THEN friend_one 
            END 
        FROM friends 
        WHERE status = '1')
    ) AND (status = '1' OR ($date - last_login) <= 300)

所以这就是我想要的结果

Logged as: khrisna
Friend list: Ben, Alpha, Ralph
All User: Ben, Alpha, John, Mark, Zayn

Online friend list: Ben, Alpha

Another online user: John, Mark, Zayn

有人可以帮助我达到我想要的结果吗？

---

更新

users表

friends表

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我想为结果制作类似的东西

  

在线用户：Khrisna Gunanasurya //登录帐户

     

在线朋友列表：Alpha，John //登录帐户的在线朋友

     

其他在线用户：Mark，Ralph //登录的其他用户，而非登录帐户的朋友

Answer 1

一种方法：

获取所有在线朋友

SELECT *
  FROM
(
  SELECT CASE WHEN friend_one = ? THEN friend_two ELSE friend_one END friend
    FROM friends
   WHERE ? IN(friend_one, friend_two)
     AND status = 1
) f JOIN users u
    ON f.friend = u.id_user
 WHERE status = 1 OR last_login >= UNIX_TIMESTAMP() - 300;

获取所有在线的非朋友

SELECT *
  FROM users u 
 WHERE id_user <> ?
   AND NOT EXISTS
(
  SELECT *
    FROM friends
   WHERE ? IN(friend_one, friend_two)
     AND status = 1
     AND u.id_user = CASE WHEN friend_one = ? THEN friend_two ELSE friend_one END
)
   AND (status = 1 OR last_login >= UNIX_TIMESTAMP() - 300);

问号表示登录用户的ID值（例如Khrisna Gunanasurya）

这是 SQLFiddle 演示

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您的PHP代码可能看起来像

$sql = "SELECT *
  FROM
(
  SELECT CASE WHEN friend_one = ? THEN friend_two ELSE friend_one END friend
    FROM friends
   WHERE ? IN(friend_one, friend_two)
     AND status = 1
) f JOIN users u
    ON f.friend = u.id_user
 WHERE status = 1 OR last_login >= UNIX_TIMESTAMP() - 300";

$stmt = $pdo->prepare($sql);
$stmt->execute(array_fill(0, 2, $id));