mysqli prepare join fejl

Kode 

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'GROUP BY t.id' at line 18

PHP kode 

 $kategoriID = $_GET['kategoriID'];
 $mysql = connect();
 $stmt = $mysql->prepare("
 Select
 t.dato,
 t.brugernavn,
 t.fk_forum_kategori,
 t.indhold,
 t.overskrift,
 t.id,
 k.id,
 k.fk_forum_traad,
 k.brugernavn, 
 k.dato
 FROM
 forum_traad t INNER JOIN
 forum_kommentare k ON k.fk_forum_traad = t.id
 WHERE
 k.godkendt = 'ja'
 AND
 t.fk_forum_kategori = ? ORDER BY k.id DESC GROUP BY t.id")or die($mysql->error);
 
 
     $stmt->bind_param("i", $kategoriID);