Require reasonably random results from an SQL SELECT query within a Joomla article (Cache enabled)

Setup: Joomla website on LAMP stack

I have a MySQL table containing some records, these are queried by a simple SELECT on the Joomla article, as pasted below. This specific Joomla website has Caching turned on in Joomla's Global Configuration. I need to randomize the order in which I display the resultset, each time the page is loaded.

Regular php/mysql would offer me two approaches for this: 1. use 'order by RAND()' or any of a number of methods to allow a SELECT query to return reasonably random results. 2. once php gets the result from the SELECT into an array, shuffle the array to get a reasonably random order of array items.

However, as this Joomla instance has Caching turned ON in its Global Configuration, either of the above approaches fails. The first time I load the page the 开发者_如何学Goorder is randomized, however any further reloads do not cause the order to change, as the page is delivered from cache. The instant the Cache is disabled, both approaches (shuffle/order by rand) work perfectly. What am I missing? How do I override the Global Cache for this specific article? A very simple requirement, that is met by both php and mysql reasonably well, is blocked by the Joomla Cache that I cannot turn off.

The php that returns results from the database.

<pre>
$db = JFactory::getDBO();
$select = "SELECT id FROM jos_mytable;"; //order by RAND()
$db->setQuery($select);
echo $db->getQuery(); //Show me the Query!
$rows = $db->loadObjectList();
//shuffle($rows);
foreach($rows as $row) {
    echo "$row->id";
}

I guess you are creating a component or what?

You can consider to clean your component from the cache (perhaps conditionally) after every request:

$cache =& JFactory::getCache('your-component-name');
$cache->clean();