trim string

I need help in this basic string function. I query from the database by using while loop and the result in in array. I separated them by using "," . I want at the end of the string to be trim off. Unfortunately I tried all the string function such as chop,trim and substr but they seem like can't manage to trim the end of the string. Please help me. my coding are: $db = mysql_select_db("tkenet_db"); $query = "SELECT app_name,status FROM approval_list where doc_no='6'"; $result = mysql_query($query,$db); while($data = mysql_fetch_row($result)){ $cc .= $h->get_email($data[0]).","; if ($data[1] != 'Y') { $all_yes = 1;} } trim($cc);