using System;

using System.Collections.Generic;

using System.Linq;

namespace ConsoleApplication19

{

    class Program

    {

        static void Main(string[] args)

        {

            int[] arr1 = { 1, 2, 3 };

            int[] arr2 = { 2, 3, 999 };

            // 메소드 기반 쿼리식

            //arr1의 수를 1증가 한값이 arr2와 같은 arr1의 값을 출력

            var res1 = arr1.Join<int, int, int, int>(arr2,

                                                       x => x + 1,

                                                       y => y,

                                                       (x, y) => x);

            foreach (var r in res1)   Console.Write(r + " ");

            Console.WriteLine("\n-------------");

            //쿼리식 기반

            //arr1의 수를 1증가 한값이 arr2와 같은 arr1의 값을 출력

            var res2 = from x in arr1

                       join y in arr2 on (x + 1) equals y

                       select x;

            foreach (var r in res1) Console.Write(r + " ");

            Console.WriteLine("\n-------------");

        }

    }

}

[결과]

1 2

-------------

1 2

-------------