C#连接数据库在控制台输出结果集（示例）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;

namespace dbConnectionTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string connstring = "Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=dbName;Data Source=serverName";
            string sqlstring = "select top 5 column1,column2,column3 from tableName";

            SqlConnection conn = new SqlConnection(connstring);
            conn.Open();

            SqlCommand cmd = new SqlCommand(sqlstring, conn);
            SqlDataReader reader = cmd.ExecuteReader();

            Console.Write("column1\tcolumn2\tcolumn3\n");
            while (reader.Read()) 
            {
                string column1 = reader.GetString(reader.GetOrdinal("column1"));
                string column2 = reader.GetString(reader.GetOrdinal("column2"));
                string column3 = reader.GetString(reader.GetOrdinal("column3"));

                Console.Write("{0}\t{1}\t{2}\n", column1, column2, column3); 
            }
            conn.Close();
            Console.ReadKey(true);//暂停
        }
    }
}

using System;
using System.Data.SqlClient;

namespace dbConnectionTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string connstring = @"Data source=1card1-hzc;Integrated Security=SSPI;Initial Catalog=DemoDB";
            string sqlstring = "SELECT [id],[hashid] FROM [dbo].[tab]"; 
            using (SqlConnection conn = new SqlConnection(connstring))
            {
                try
                {
                    SqlCommand cmd = new SqlCommand(sqlstring, conn);
                    conn.Open();
                    SqlDataReader r = cmd.ExecuteReader();
                    Console.WriteLine("id       hashid");
                    while (r.Read())
                        Console.WriteLine("{0}      {1}", r[0].ToString(), r[1].ToString());
                    conn.Close();
                }
                catch (SqlException se)
                {
                    Console.WriteLine(se);
                }
                Console.ReadLine();
            }
        }
    }
}