PostgreSQL support

are there anyone test webcal module with postgresql?

this query belong to mysql and not valid with postgresql
$sql = "UPDATE $app_user_table u, $app_session_table s SET u.access = '".time()."' WHERE s.sid = '$sid' AND u.uid = s.uid AND s.uid <> 0";

query for postgresql
$sql = "UPDATE $app_user_table SET access = '".time()."' FROM $app_session_table s WHERE s.sid = '$sid' AND $app_user_table.uid = s.uid AND s.uid <> 0";

plz test my code above. thx