how to delet the coments while clearing data

[love_444]

how to delet the coments on a fporm post or say a shout ... where the commests are saved in difrent sql
normaly clear data pr deleting the old post is done as taking there post time like this

$altm = time()-(5*24*60*60);

echo "<br/>";

$res = mysql_query("DELETE FROM shout WHERE shtime<'".$altm."'");

if($res){

echo "<img src=\"images/ok.gif\" alt=\"O\"/>Shouts Older Than 5 days were deleted";

}else{

echo "<img src=\"images/notok.gif\" alt=\"X\"/>Database Error!";

} 

but in this the comment on shout or any outher post is not deleted

when the comment is saved in another table say shoutcomment .....

can any one plzz give a hint how to make it done

[arnage]

First select data by some criteria (poster id or something) and than do while loop with deleting on selected.
That is just to delete from some past time.