php - Mysql:将 3 个表与多个 'where' 连接起来？

Question

我试图在一种情况下将一个表连接到另一个表，然后在另一种情况下将表连接到另一个表。你能做到吗？如果能，正确的语法是什么？我一直在尝试这个，但它不起作用:

$check = $members->prepare("select users.fname, users.lname, groups.groupid, attributes.max 
    from users 
    JOIN groups 
         on users.user_id = groups.userid 
    where groups.userid = ? 
    LEFT JOIN attributes 
         on users.user_id = attributes.userid 
    where attributes.groupid = ?");
$check->bind_param('ss', $_SESSION['token'][1], $which_group);
$check->execute();

干杯。

Answer 1

只需使用........ AND

$check = $members->prepare("select users.fname, users.lname, groups.groupid, attributes.max 
    FROM users 
    JOIN groups 
         ON users.user_id = groups.userid 
         AND groups.userid = ? 
    LEFT JOIN attributes 
         ON users.user_id = attributes.userid 
         AND attributes.groupid = ?