PHP和MySQL -如何使用order by desc和limit 1更新单表中的单行

Question

大家好，实际上我正在尝试维护ip的用户日志，用户的上次登录时间和上次注销时间，在php和mysql中工作。用户登录时成功存储ip和登录时间，但在注销时更新注销时间，同时更新同一用户id的所有注销时间，我只想更新用户id的最后一次注销时间，无论他是否登录了任何次数。有没有人能帮助我呢？

我的代码是-

if (isset($_SESSION['userId']) && !empty($_SESSION['userId'])) {
    include "connection.php";
    $userId = $_SESSION['userId'];

    $sqluserlogs = "UPDATE userlogs SET LastLogout = now()
    WHERE uid = '$userId' ORDER BY uid DESC LIMIT 1";

    if (mysql_query($sqluserlogs, $conn)) {
        //echo 'success';
    } else {
        //echo 'failed';
    }
}

更新的查询-

  $sqluserlogs = "UPDATE userlogs SET LastLogout = now() WHERE
   uid = '$userId' ORDER BY ulogID DESC LIMIT 1";

提前感谢

Answer 1

尝试联接：

 "UPDATE userlogs AS UpdateTable
     INNER JOIN (
         SELECT JoinTable.id
         FROM userlogs AS JoinTable
         WHERE JoinTable.uid = '$userId'
         ORDER BY uid DESC
         LIMIT 1) 
                 AS source ON source.id = UpdateTable.id
    SET LastLogout = now()";