php传参的有关问题

function getStaffListByID($con){
        global $idn,$id,$pic,$name;
        $sel = "select id,pic,name from student;";
        $ret = pg_Exec($con,$sel);
        $idn = pg_NumRows($ret);
        for ( $i=0; $i<$idn; $i++ ) {
                $id[$i]             = pg_Result($ret, $i, "id");
                echo '$id[$i]'.$id[$i];
                $lid = $id[$i];
                getStaffListByLID($con,$lid);
                $pic{$id[$i]}     = pg_Result($ret, $i, "pic");
                $name{$id[$i]}      = pg_Result($ret, $i, "name");                
        }
    }
    
    function getStaffListByLID($con,$lid){
        global $tidn,$tid,$tpic,$tname;
        echo 'ereree'.$lid;
        $sel = "select tid,tpic,tname from teacher;";
        $ret = pg_Exec($con,$sel);
        $tidn = pg_NumRows($ret);
        for ( $i=0; $i<$tidn; $i++ ) {
                $lid[$i]             = pg_Result($ret, $i, "tid");
                $lpic{$id[$i]}     = pg_Result($ret, $i, "tpic");
                $lname{$id[$i]}      = pg_Result($ret, $i, "tname");
        }
    }