keuren binnen

<?php
//buat variabel $intervals sebagai suatu array
$intervals=array();
foreach($product as $products) :
  $slangtype = explode ("-",$products['product_slangtype']);
?>
  <tr class="task  Hoog" id="project-0">
    <td align="center" valign="middle">
      <input type="checkbox" name="projectslist[]" value="#project-0" checked="checked">
    </td>
    <td><?php echo $products['product_rn']; ?></td>
    <td class="title">
      <div class="task_title">
        <a href="http://mvdb-certificaten.ebbersmediaweb.nl/index.html#project-0"
           title="Bewerken" class="edit_slangtype"
           rel="projects/save.php">
          <?php  echo $slangtype[1] ?>
        </a>
        <div class="quick_options fr">
          <a href="product_edit.php?idp=<?php echo $products['id_product'] ?>"
             title="Bewerken" class="do_edit"></a>
          <a href="" onclick="return confirm('Delete this data?')"
             title="Verwijderen" class="do_delete"></a>
        </div>
      </div>
  </td>
  <td>
    <?php echo date('d-m-Y',strtotime($products['product_created'])); ?>
  </td>
<?php
$res=strtotime(date('d-m-Y',strtotime($products['product_created'])).'+'.$products['product_k_freq'].' month');
$interval=ceil(abs($res-strtotime(date('d-m-Y')))/86400);
//check apakah $intervals utk account sesuai $products['id_user'] sudah ada?
if(isset($interval[$products['id_user']]))
{
  //jika sudah ada, tambahkan dengan nilai yg didapat
  $intervals[$products['id_user']]['product'][]=$products['product_rn'];
  $intervals[$products['id_user']]['interval']+=$interval;
}
else
{
  //jika belum ada, buat baru dan isi dengan nilai yang didapat
  $intervals[$products['id_user']]=array();
  $intervals[$products['id_user']]['interval']=$interval;
  $intervals[$products['id_user']]['product']=array();
  $intervals[$products['id_user']]['product'][]=$products['product_rn'];
}
?>
  <td><input type="text" value="<?php echo date('d-m-Y',$res); ?>"
             class="input_clean date-pick_table"></td>
  <td><?php echo $interval; ?> dagen</td>
  <td><?php echo $products['product_fabrikant'] ?></td>
  <td>
    <a class="open_accordion"
       href="keuring_add.php?idp=<?php echo $products['id_product']; ?>"
       title="">Keuren</a>
  </td>
</tr>
<?php
endforeach;
foreach($intervals as $id_user => $interval)
{
  if($interval['interval']==60)
  {
    //kirim email ke account $id_user
  }
}
?>