public function getInvoice($id){
$query = "SELECT * FROM `".$this->db_table_invoice."` AS t1 JOIN `".$this->db_table_user."` AS t2 ON t1.`user_id` = t2.`id` JOIN `".$this->db_table_org."` AS t3 ON t1.`org_id` = t23.`id` WHERE t1.`id` = ?";
$stmt = $this->db->prepare($query);
$stmt->execute(array($id));
return $stmt->fetch();
}