General Support: Collections Order by Last Modified

Hi Guys

I am trying to modify the way my COLLECTIONS sort/order. After a search i found out that with the following code i can sort/order them by alphabetical order ascending or descending:

$sql = "SELECT * FROM `".$TABLE_PREFIX."collections` WHERE id IN ($imlist) LIMIT ".$from.",".$config["thumb_num"];

Change to:

$sql = "SELECT * FROM `".$TABLE_PREFIX."collections` WHERE id IN ($imlist) ORDER BY `name` DESC LIMIT ".$from.",".$config["thumb_num"];

This works perfectly fine, but i want to be able to sort on LAST CHANGED COLLECTION. Is this possible to do or is that currently impossible ? I hope some one can help me out here ;)

Thnx in advance