我如何得到mysql数据库id随机回声

我已经创建了一个PHP/mysql搜索数据库以下教程在线。一切都很顺利。我只是想知道如何在数据库中获得以随机顺序显示的结果。

目前的结果显示在一个数字顺序根据其ID号在mysql数据库。我想知道如何随机显示结果?

使用$id调用id。下面是PHP:

<?php
$button = $_GET ['submit'];
$search = $_GET ['search'];
if(strlen($search)<=1)
echo "Search term too short";
else{
echo "<h1>Dislpaying results for <b>$search</b> <hr size='1'></h1></br>";
mysql_connect("localhost","dobhgc767545ch2","jhjhghtyutuhjh");
mysql_select_db("doorcouhjhjh2");
$search_exploded = explode (" ", $search);
foreach($search_exploded as $search_each)
{
$x++;
if($x==1)
$construct .="keywords LIKE '%$search_each%'";
else
$construct .="OR keywords LIKE '%$search_each%'";
}
$constructs ="SELECT * FROM search WHERE $construct";
$run = mysql_query($constructs);
$foundnum = mysql_num_rows($run);
if ($foundnum==0)
echo "Sorry, there are no matching result for <b>$search</b>.</br></br>1.
Try more general words. for example: If you want to search 'how to create a website'
then use general keyword like 'create' 'website'</br>2. Try different words with similar
 meaning</br>3. Please check your spelling";
else
{
echo "$foundnum results found !<p>";
$per_page = 9;
$start = $_GET['start'];
$max_pages = $foundnum / $per_page;
if(!$start)
$start=0;
$getquery = mysql_query("SELECT * FROM search WHERE $construct LIMIT $start, $per_page");
while($runrows = mysql_fetch_assoc($getquery))
{
$title = $runrows ['title'];
$description = $runrows ['description'];
$link = $runrows ['link'];
$image = $runrows ['image'];

echo "
<div class='"pagination'" style='"display:inline'"><ul style='"background-color:#'"><li><div      class='"span3_search'"><div class='"title_bg'"><h2><a href='$link'><b>$title</b>    </a></h2></div><div class='"result_img'"><a href='$link'><img id='"result_img'" src='"$image'" /></a>    </div><div class='"result_desc'"><p>$description</p></div><div class='"result_link'"><br />
<a href='$link'>$link<br /><br /></a><p></div></div></li></ul></div>
";

?>