$products_cart_limit = 0;
      $limit_query = "SELECT
                      IF(ps.products_cart_limit IS NULL, p.products_cart_limit, ps.products_cart_limit)
                      as products_cart_limit
                      FROM " . TABLE_PRODUCTS . " p
                      LEFT JOIN " . TABLE_PRODUCTS_STORES . " ps
                      ON (p.products_id = ps.products_id AND ps.stores_id = '" . STORE_ID  . "')
                      WHERE p.products_id = '" . (int)$products_id . "'";
      $limit_result = tep_db_query($limit_query);
      if (tep_db_num_rows($limit_result)) {
      	$limit_array = tep_db_fetch_array($limit_result);
      	$products_cart_limit = $limit_array['products_cart_limit'];
      }