JDBC 从 Access 表中选择最大值

每当我运行以下代码时，即使该列存在于我的表中，我也会收到错误“未找到列”。我正在使用access数据库，请寻求帮助

public class Trial1 {
public static void main (String[]args){

            try{
                Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");  
                String url = "jdbc:odbc:SENSOR";
                String user = "";
                String pass = "";
                Connection con = DriverManager.getConnection(url,user,pass);
                Statement stmt  = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);                          //stmt代表資料庫連接成功


                ResultSet rs = stmt.executeQuery("select MAX(LevelNum) from NList");
                 if (rs.next()){

                    int w = rs.getInt("LevelNum");
                   int x= 3;                             

                double i = Math.pow(2, (w-x))-1;
                System.out.printf("i is  %f",i);}


                stmt.close();
                con.close();

            }catch(Exception e)
            {
                System.out.println("Error" + e);
            }

}

}

假设错误是在您获得结果时而不是在执行查询时发生的，您可能需要这样的东西

// ...
ResultSet rs = stmt.executeQuery("select MAX(LevelNum) as maxLevel from NList");
if (rs.next())
{
    int w = rs.getInt("maxLevel");

    // ... etc.
}