Questions about passing parameters in php-php Tutorial

I want to call the getStaffListByLID function in the loop of the getStaffListByID function, but the value of lid in getStaffListByLID does not appear to be passed. what can I do? PHPcodefunctiongetStaffListByID ($ con) {global $ idn, $ id, $ pic, $ name; php parameter passing problem
I want to call the getStaffListByLID function in the loop of the getStaffListByLID function, but it seems that the value of lid in getStaffListByLID is not passed. what can I do?

PHP code

  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");        }    }

------ Solution --------------------
I do not believe
Add a var_dump ($ lid) to the getStaffListByLID function );