Question

我在尝试从mySQL获取数据时遇到错误：

Additional information: Could not find specified column in results: admin

我的代码是：

public int getLevel()
    {
        string sqlCommand = "Select level from users where username = 'admin'";
        int value = 0;

        MySqlConnection con = new MySqlConnection("host=111.222.111.222;user=MYUSERNAME;password=MYPASSWORD;database=tcg;");
        MySqlCommand cmd = new MySqlCommand(sqlCommand, con);

        con.Open();

        MySqlDataReader reader = cmd.ExecuteReader();

        while (reader.Read())
        {
            value += int.Parse(reader.GetString("admin"));
        }
        return value;
    }

Answer 1

尝试：

 public int getLevel()
 {
     int value = 0;
     using(MySqlConnection con = new MySqlConnection("host=45.37.80.181;user=MYUSERNAME;password=MYPASSWORD;database=tcg;"))
     {
         con.Open();
         using(MySqlCommand cmd = con.CreateCommand())
         {
             cmd.CommandText = "Select level from users where username = @ad";
             cmd.Parameters.AddWithValue("@ad","admin");
             MySqlDataReader reader = cmd.ExecuteReader();

             while (reader.Read())
             {
                 value += int.Parse(reader[0]);
             }
        }
        con.Close();
     }
     return value;
}

如果您只有一个管理员，请使用：

public int getLevel()
 {
     int value = 0;
     using(MySqlConnection con = new MySqlConnection("host=45.37.80.181;user=MYUSERNAME;password=MYPASSWORD;database=tcg;"))
     {
         con.Open();
         using(MySqlCommand cmd = con.CreateCommand())
         {
             cmd.CommandText = "Select level from users where username = @ad";//add Order by if you need to
             cmd.Parameters.AddWithValue("@ad","admin");
             value += Convert.ToInt32(com.ExecuteScalar());//this assumes you will get an integer value

        }
        con.Close();
     }
     return value;
}

C＃ - 从mySQL数据库获取数据时出错

1 个答案: