如何在回答结束时删除调查变量

我有以下代码：

<?php
ini_set("error_reporting",0);
include_once 'init/init.funcs.php';
if (isset($_GET['pollid']))
    $_SESSION['pollid']=(int) $_GET['pollid'];
else
    $_SESSION['pollid'] = 0;
    echo 'kysitlus l6ppenud';
$questions = array();
if (!isset($_SESSION['answering'])) {
    $result = mysql_query('SELECT * from katse_kysimused where kysimustik_id="' . $_SESSION['pollid'] . '"');
    while($row = mysql_fetch_assoc($result)) {
        $questions[] = $row['kysimus'];
        }
    $_SESSION['answering']['questions'] = $questions;
    $_SESSION['answering']['index'] = 0;
    $_SESSION['answering']['count']=count($questions);
}
    $answer = $_POST['answer'];
    $x = $_SESSION['answering']['index'];
    $result3 = mysql_query('SELECT tyyp_id FROM katse_kysimused where kysimus= "' . $_SESSION['answering']['questions'][$x] . '"');
    $type = mysql_result($result3, 0);
    if ($type=='3'){
        echo "<meta http-equiv='refresh' content='0;url=http://localhost/Praks/valikvastustega_kysimusele_vastamine.php'>";
        }
    if ($type=='1'){
            echo "<meta http-equiv='refresh' content='0;url=http://localhost/Praks/tekstkysimusele_vastamine2.php'>";
        }
if(isset($_POST['submit'])){
    if(isset($_POST['option'])){
    $answer=$_POST['option'];
    }
    $result2 = mysql_query('SELECT kysimus_id FROM katse_kysimused where kysimus= "' . $_SESSION['answering']['questions'][$x -1] . '"');
    $q_id = mysql_result($result2, 0);
    mysql_query('INSERT INTO katse_vastused2 (id, vastus,kysimus_id, vastustik_id) VALUES (NULL,"' . $answer . '","' . $q_id . '","1")');
}
$_SESSION['answering']['index']++;
?>

它是从kysimustik_id="' . $_SESSION['pollid']所在的数据库中打印出答案的代码。（这不是完整的代码，还有两个单独的文件用于回复和回答问题）。

我的问题是，我应该在代码中写入什么以及在哪里写入，这样在回答结束时就会删除$_SESSION["swering"]变量，这样我就可以在同一会话中再次回答其他调查，而无需关闭和重新打开浏览器。

编辑：

我更改了代码，现在我可以多次回答调查，但这永远是我回答的第一个调查，我从url插入哪个民意测验并不重要，我的代码现在看起来是这样的：

<?php
ini_set("error_reporting",0);
include_once 'init/init.funcs.php';
if (isset($_GET['pollid']))
    $_SESSION['pollid']=(int) $_GET['pollid'];
else
    $_SESSION['pollid'] = 0;
    //echo 'kysitlus l6ppenud';
$questions = array();
if (!isset($_SESSION['answering'])) {
    $result = mysql_query('SELECT * from katse_kysimused where kysimustik_id="' . $_SESSION['pollid'] . '"');
    while($row = mysql_fetch_assoc($result)) {
        $questions[] = $row['kysimus'];
        }
    $_SESSION['answering']['questions'] = $questions;
    $_SESSION['answering']['index'] = 0;
    $_SESSION['answering']['count']=count($questions);
}
if ($_SESSION['answering']['index']==$_SESSION['answering']['count']){
if(isset($_SESSION['answering'])){
  unset($_SESSION['answering']);
  unset ($_SESSION['answering']['questions']);
  unset ($_SESSION['answering']['index']);
  unset ($_SESSION['answering']['count']);
  exit("kysitlus l6ppenud");
  }
}
    $answer = $_POST['answer'];
    $x = $_SESSION['answering']['index'];
    $result3 = mysql_query('SELECT tyyp_id FROM katse_kysimused where kysimus= "' . $_SESSION['answering']['questions'][$x] . '"');
    $type = mysql_result($result3, 0);
    if ($type=='3'){
        echo "<meta http-equiv='refresh' content='0;url=http://localhost/Praks/valikvastustega_kysimusele_vastamine.php'>";
        }
    if ($type=='1'){
            echo "<meta http-equiv='refresh' content='0;url=http://localhost/Praks/tekstkysimusele_vastamine2.php'>";
        }
if(isset($_POST['submit'])){
    if(isset($_POST['option'])){
    $answer=$_POST['option'];
    }
    $result2 = mysql_query('SELECT kysimus_id FROM katse_kysimused where kysimus= "' . $_SESSION['answering']['questions'][$x -1] . '"');
    $q_id = mysql_result($result2, 0);
    mysql_query('INSERT INTO katse_vastused2 (id, vastus,kysimus_id, vastustik_id) VALUES (NULL,"' . $answer . '","' . $q_id . '","1")');
}
$_SESSION['answering']['index']++;

?>

然后我把if ($_SESSION['answering']['index']==$_SESSION['answering']['count'])改为if ($_SESSION['answering']['index']==$_SESSION['answering']['count']+1)，现在我可以回答任何调查，但出现了新问题。当调查结束时，消息"kysitlus l6ppond"不会立即出现。我必须重新加载页面，然后会显示消息。我确信这个问题有简单的解决方案，但我不知道，我应该更改一些代码或其他东西的顺序。有人能给我指对方向吗？