i want to convert sql query to linq to sql

Hello

Use the LINQPad.
Install it on your system.

https://www.linqpad.net/

Thanks

You can download s/w for SQl To LINQ converter 

http://www.sqltolinq.com/

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

namespace ConsoleApplication1
{
    class schedule
    {
       public int ID { get; set; }
       public int nleadpk { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            List objSchedule =new List();//GetSheduleList();
            objSchedule.Add(new schedule{ID= 3,nleadpk=1});
            objSchedule.Add(new schedule{ID= 4,nleadpk=2});
            objSchedule.Add(new schedule{ID= 5,nleadpk=2});

            //Use below any query.
            var linqmaxIdList = (from obj in objSchedule
                         where (obj.nleadpk > 0 && obj.nleadpk == 1) || (obj.nleadpk == 2)
                         group obj.ID by obj.nleadpk into gkey
                         select gkey.Max()
                         ).ToList();

            var lemdamaxIdList = objSchedule
                                .Where(w => (w.nleadpk > 0 && w.nleadpk == 1) || w.nleadpk == 2)
                                .GroupBy(g => g.nleadpk, g => g.ID, (gKey, gValue) => gValue.Max()).ToList();

            foreach (var max in lemdamaxIdList)
                       {
                           Console.WriteLine(max);
                       }
                  
        }
    }
}

 try this 


http://weblogs.asp.net/hajan/linqer-a-nice-tool-for-sql-to-linq-transition