我無法在更改密碼頁面中將密碼更新為新密碼，而且完全沒有錯(cuò)誤，所以找不到哪個(gè)是不正確的部分。我檢查了 MySQL 表，它沒有更新。有人可以幫忙查一下嗎？謝謝。PHP代碼 include "../setting/config.php"; session_start();$btnchange = filter_input(INPUT_POST, "btnchange");if(isset($btnchange)){    $username = filter_input(INPUT_POST, "username");    $password = filter_input(INPUT_POST, "password");    $query2 = "SELECT username from registered_accounts where username='$username'AND password='$password'";    $query_run=mysqli_query($conn, $query2);    $level = mysqli_fetch_array($query_run);    if(count(fetchAll($query2)) > 0){ //this is to catch unknown error.                  foreach(fetchAll($query2) as $row){                    if ($row['username'] == $username && $row['password'] == $password)                     {                        $update_query2= "UPDATE registered_accounts set password='$password' where username='$username'";                        $update_query_run=mysqli_query($conn, $update_query2);                        if ($update_query2)                        {                            echo "<script>alert('Password has been changed successfully.')</script>";                        }                        else{                            echo "<script>alert('Password has been failed to change.')</script>";                        }}}}}?>身體<form action="<?= $_SERVER['PHP_SELF'] ?>" method="post">    <input type="text" class="text" name="username" placeholder="Username" value="" required autofocus>    <input type="password" placeholder="Password" name="password" value="" required autofocus>    <div class="submit"><input type="submit" value="Submit" name="btnchange"></div></form>注冊(cè)賬戶表