I receive a php notice in unidentified raw variable

I receive a php notice in unidentified raw variable

would appreciate your help to tackle this

functions.php

<?php
$item = $results->fetch();
if (empty($item)) return $item;
try {
    $results = $db->prepare("
        SELECT fullname, role 
        FROM Media_People
        JOIN People ON Media_People.people_id = People.people_id
        WHERE Media_People.media_id = ?;
        ");
    $results->bindParam(1,$id, PDO::PARAM_INT);
    $results->execute();
} catch (Exception $e) {
  echo "Data is not received";
  exit;
}
while ($row = $results->fetch(PDO::FETCH_ASSOC)) {
    $item[$row["role"]][] = $raw["fullname"];
}
return $item;
}

details.php

<?php echo implode(", ", $item["artist"]); ?>

Notice: Undefined variable: raw in /Applications/XAMPP/xamppfiles/htdocs/projects/inc/functions.php on line 49 array(19) { ["media_id"]=> string(1) "9" [0]=> string(1) "9" ["title"]=> string(30) "Beethoven: Complete Symphonies" [1]=> string(30) "Beethoven: Complete Symphonies" ["category"]=> string(5) "Music" [2]=> string(5) "Music" ["img"]=> string(23) "img/media/beethoven.jpg" [3]=> string(23) "img/media/beethoven.jpg" ["format"]=> string(2) "CD" [4]=> string(2) "CD" ["year"]=> string(4) "2012" [5]=> string(4) "2012" ["genre"]=> string(9) "Classical" [6]=> string(9) "Classical" ["publisher"]=> NULL [7]=> NULL ["isbn"]=> NULL [8]=> NULL ["artist"]=> array(1) { [0]=> NULL } }