Question

I want to write a MySql statement that will connect to the database, select a column from the table, then output that data to a text file to a specific location on my computer. I have searched the internet for a couple days now and don’t seem to find the answer I am looking for. I am fairly new to c#, MySql, and Visual Studio. I am just trying to learn how to write the correct statements and get the desired result. Any help would be greatly appreciated.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MySql.Data.MySqlClient;
using MySql.Data;
using System.Windows.Forms;
using System.IO;

namespace NewPractice
{
    public class Connect
    {
        static void Main()
        {
            string results = @"server=111.111.11.111; userid=anyone;
                password=anypassword; database=anydatabase";    
            MySqlConnection conn = null;

            try
            {
                conn = new MySqlConnection(results);
                conn.Open();
                //Console.WriteLine(
                File.WriteAllLines(
                    @"C:\Documents and Settings\anyone\My Documents\Tests\testoutput.txt", 
                    results.ToArray());
            }
            catch (MySqlException ex)
            {
                Console.WriteLine("Error: (0)", ex.ToString());
            }
            finally
            {
                if (conn != null)
                {
                    conn.Close();
                }
            }
        }      
    }
}

Answer 1

You’re writing the contents of the result string to the file, not the data you’re attempting to select. You need to run a sql command and get a SqlDataReader object to write your data to the file.

string results = @"server=111.111.11.111; userid=anyone; 
    password=anypassword; database=anydatabase";

MySqlConnection connection = new MySqlConnection(results);
MySqlCommand command = connection.CreateCommand();
MySqlDataReader reader;
command.CommandText = "select * from mycustomers";
connection.Open();
reader = command.ExecuteReader();
using(var sw = new StreamWriter("C:\MyPath\MyFile.txt"))
{
    while (reader.Read())
    {
        var row = (IDataRecord)reader;
        sw.WriteLine(row["myColumn"]);
    }
}
connection.Close();