Får en SQL fejl ?

Får denne fejl:
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 'SQL' at line 1

Det er i den SQL der hedder $SQL2, har prøvet at skrive den ud, men kan ikke få lov?

Anyway, min kode ser sådanne ud:

Function RtrnImage($Doc_ID) {

    $SQL = "SELECT template FROM dokumenter WHERE doc_id = '$Doc_ID' AND active = '1'";
   
    $mq = mysql_query(SQL) or die(mysql_error());

    if(mysql_num_rows($mq) > 0) {
       
        $gettmpl = mysql_fetch_assoc($mq);
       
        $tmpl = $gettmpl['template'];
       
        if($tmpl == "1") {
       
            $append = '<div class="img_item_left">';
       
        }

        if($tmpl == "2") {

            $append = '<div class="img_item_right">';
       
        }

        $SQL2 = "SELECT * FROM doc_images WHERE doc_id = '$Doc_ID' ORDER BY image_id";
        echo $SQL2;
        $mq2 = mysql_query($SQL2) or die(mysql_error());

        if (mysql_num_rows ($mq2)>0) {
            while($row = mysql_fetch_assoc($mq2)){
       
            $image_type = $row["image_type"];
            $image = $row["image"];
            $image_id = $row['image_id'];

            Header ("Content-type: $image_type");
           
            $append .= '<div class="img">';         

            return $image;

            $append .= '<img src="vis_billede.php?imageid=' . $image_id .'" />';

            $append .= '</div>';

            }
        }

        $append .= '</div>';

        echo $append;

    }

}

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