using System;

using System.Linq;

using System.Collections.Generic;

​

public class Emp

{

    public string Ename

    {

        get;

        set;

    }

​

    public decimal Sal

    {

        get;

        set;

    }

​

    public string Deptno

    {

        get;

        set;

    }

}

​

public class Program

{

    public static List<Emp> Emps = new List<Emp>{new Emp{Ename = "Test1", Sal = 1000, Deptno = "x1"}, new Emp{Ename = "Test2", Sal = 2000, Deptno = "x1"}, new Emp{Ename = "Test3", Sal = 3000, Deptno = "x2"}, new Emp{Ename = "Test4", Sal = 5000, Deptno = "x2"}, new Emp{Ename = "Test5", Sal = 500, Deptno = "x3"}, new Emp{Ename = "Test6", Sal = 70, Deptno = "x3"}, };

    public static void Main()

    {

        var result = Emps.GroupBy(g => g.Deptno).SelectMany(a => a.Where(b => b.Sal == a.Min(c => c.Sal)));

        foreach (var r in result)

        {

            Console.WriteLine(r.Deptno + " " + r.Ename + " " + r.Sal);

        }

    }

}