It is not the nicest solution but it will work (if the dates are allways stored like this in database 0000-00-00):
$date_from_db;
$year = substr($date_from_db,0,4);
$month = substr($date_from_db,5,7);
$day = substr($date_from_db,8,10);
echo $year."/".$month."/".$day;//this would echo your date in wanted format
Similar is for the time part...