public String getOrdernumberByCarnumberAndPhonenumber(Statement statement,String carnumber,String phonenumber)//根据预定手机号和车牌号查找订单
	{
		String result = null;
		sql = "select ordernumber from ParkRelation where carnumber = '" + carnumber +"' and phonenumber = "+phonenumber+"'";
		try 
		{
			ResultSet rs = statement.executeQuery(sql);
			while (rs.next()) {
				result = rs.getString("ordernumber");
			}
		} 
		catch (SQLException e) 
		{
			System.out.println("Error! (from src/Fetch/ParkRelation.getOrdernumberByCarnumberAndOrdertime())");
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return result;
	}