@Prog! - ASP.NET(C#) AJAX -

using System;
using System.Linq;
using System.Collections.Generic;
using System.IO;

namespace ConsoleApplication5
{
    class Program
    {
        static void Main(string[ args)
        {
            using (Test1 db = new Test1(Settings1.Default.ConnectionString))
            {
                StreamWriter sw = new StreamWriter(@"d:\log.txt");
                sw.AutoFlush = true;
                TextWriter tw = TextWriter.Synchronized(sw);

                db.Log = tw;

                var rs = from t1 in db.Table_1
                         join t3 in db.Table_3
                         on new { t1.ID } equals new { t3.ID }
                         select new { t1.ID, t3.FirstName, t3.LastName };

                foreach (var r in rs) Console.WriteLine(r);
            }

            Console.Read();
        }
    }
}

SELECT [t0].[ID], [t1].[FirstName], [t1].[LastName]
FROM [dbo].[Table_1] AS [t0]
INNER JOIN [dbo].[Table_3] AS [t1] ON [t0].[ID] = [t1].[ID]
-- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.21022.8