public function result_multi($sql) {

    try {
        mysqli_multi_query($this->db_connection,$sql);
        $result=mysqli_store_result($this->db_connection);
        $row=mysqli_fetch_row($result);
    }

$b=new DB;
$sql="INSERT INTO payout (mid, type, datetime) VALUES ('0','BC',
NOW());SELECT LAST_INSERT_ID();";
$b->result_multi($sql);