selecione o valor da opção do banco de dados no selecionado

while($rows=mysql_fetch_assoc($query)){
?>
    <form method=\"POST\" action=\"edit.php\">
    <input type ='hidden' name='ID' value = '<?php echo $rows['ID'];?>'>
    <select name ="pnames">
        <?php foreach ($arrayproducts as $key => $value) {
        ?>  
            <option value = "<?php echo $key; ?>" 
            <?php
                if ($key == $productName){
                    echo 'selected="selected"';
                } 
            ?> >
            <?php echo $value; ?> 
            </option>
     <?php } //end foreach ?>   
   </select>
<?php }//end while ?>

if ($value == $productName){