MrFreeman94

это вообще реально?

foreach ($arr as $item) {
  $id = $item['id_product_attribute'];
  if (!isset($result[$id])) {
    $result[$id] = $item;
  } else {
    $result[$id]['attribute_name'] .= ', '.$item['attribute_name'];
  }
}

$result = array_reduce(
	$data,
	function($res, $el) {
		if (isset($res[$el["id_product_attribute"]])) {
			$res[$el["id_product_attribute"]] .= ", " . $el["attribute_name"];
		} else {
			$res[$el["id_product_attribute"]] = $el["attribute_name"];
		}
		return $res;
	},
	[]
);

var_export($result);

var myId= 0;
$(document).find('button').each(function(){
   myId++;
   $(this).attr("id", "id"+myId);
});

$('.lb-test').click(function () {
	$(this).toggleClass('minus-lb');
	if ($(this).hasClass('minus-lb')) {
		$(this).children('.popup-lb-item').fadeIn(300);
	} else {
		$(this).children('.popup-lb-item').fadeOut(300);
	}
});