PHP 和 MySQL 问题

Question

如何检查 $user_id 和 $logged_user 是否同时在 MySQL 表字段 userID 和 friendID 中>

MySQL 代码。

$user_id = 2;
$logged_user = 1;

$dbc = mysqli_query($mysqli,"SELECT * 
                             FROM users_friends 
                             WHERE userID = '" . $logged_user . "' 
                             AND friendID = '" . $user_id . "'");

Answer 1

如果您想检查这两种组合

SELECT *
FROM users_friends 
WHERE (userID = '" . $logged_user . "' 
        AND friendID = '" . $user_id . "')
    OR (friendID  = '" . $logged_user . "' 
        AND userID = '" . $user_id . "')"