Php 获取上次登录的详细信息

我开发了登录系统。它工作得很好。现在我想得到最后的登录日期和时间，并显示它。显示部分正常。如果登录成功，我尝试用这段代码更新数据库中的logtime字段

$query      =   "SELECT * FROM user WHERE email='$email' AND passwordR='$password' AND status='1' ";

    $result     =   mysqli_query($con,$query)or die(mysqli_error($con));
    $num_row    =   mysqli_num_rows($result);
    $row        =   mysqli_fetch_array($result);

    if( $num_row ==1 ) {
            $_SESSION['user_name']  =   $email;
            $sql="UPDATE user SET logtime = now()";
            mysqli_query($con,$query)or die(mysqli_error($con));
                       }

我的日志时间行定义如下

 `logtime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

日志时间有多少次没有更新。为什么是

$sql="UPDATE user SET logtime = now()";

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不可能吗？

那应该可以

$sql="UPDATE user SET logtime = now() WHERE email='$email' AND passwordR='$password' AND status='1'";

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这应该能奏效

$sql="UPDATE user SET logtime = now() WHERE email='$email' AND passwordR='$password' AND status='1'";