public function add_receipt($receipt_data) { //new receipt $receipt = new Receipt(); // get data $receipt->get_data_from_array($receipt_data); TEST($receipt->json_encode(false)); //compute the sequence of sql to add this receipt to db $comma_seperated_list = $receipt->get_seperated_list(); TEST($comma_seperated_list); //mysqli_query($this->db, "CALL test('$comma_seperated_list');"); }