Ummm, might be missing something, but as long as the query is valid and returns results, all you'd have to do use use a
$row = mysql_fetch_array()
on the result set in a do..while loop. In the loop, append the $row to a string e.g.
$e-mail_list .= $row[0].";"
and then print $e-mail_list after the loop. Someone will have to confirm if you do or don't have to escape the ";" in a string, though I don't think that you have to.
HTH
glj