using System;

using System.Linq;

using System.Collections.Generic;

​

public class Table1

{

    public int Table1_id;

    public string Field1 = "This is Field1";

    public string Field2 = "This is Field2";

    public Table1(int id)

    {

        Table1_id = id;

    }

}

​

public class Table2

{

    public int Table2_id;

    public string FieldA = "This is FieldA";

    public string FieldB = "This is FieldB";

    public Table2(int id)

    {

        Table2_id = id;

    }

}

​

public class Program

{

    public static void Main()

    {

        var ListOfTable1 = new List<Table1>()

        {

        new Table1(0), new Table1(1), new Table1(2)}

​

        ;

        var ListOfTable2 = new List<Table2>()

        {

        new Table2(0), new Table2(0), new Table2(0)}

​

        ;

 var query = ListOfTable1

                .GroupJoin(ListOfTable2, (table1 => table1.Table1_id), (table2 => table2.Table2_id),

                    (table1, table2) => new  

                                        { 

                                            Id = table1.Table1_id,

                                            field1 = table1.Field1, 

                                            field2 = table1.Field2, 

                                            manySubObjects = (table2.Count() > 0) 

                                                ? (from t in table2 select new  { fielda = t.FieldA, fieldb = t.FieldB}).ToList()

                                                : null 

                                        }).ToList();

        foreach (var result in query)

        {

            if(result != null)

            {

                Console.Write(result.Id + ", ");

                Console.Write(result.field1 + ", ");

                Console.Write(result.field2 + ", ");

                Console.Write((result.manySubObjects == null ? 0 : result.manySubObjects.Count()));                 

                Console.WriteLine();

            }

​

        }

    }

}