Selecting all the rows based on distinct column value

I think you can implement it easily by LINQ.
Here is my code sample .

using System;
using System.Linq;
using System.Text;
using System.Data;

public class Test
{
    public static void Main()
    {
        var table = new DataTable();
        table.Columns.Add("Column1");
        table.Columns.Add("Column2");
        table.Columns.Add("Column3");

        table.LoadDataRow(new object[] { "A", "xyz", "pqr" }, false);
        table.LoadDataRow(new object[] { "A", "asd", "poi" }, false);
        table.LoadDataRow(new object[] { "B", "zxc", "mnb" }, false);
        table.LoadDataRow(new object[] { "B", "123", "456" }, false);

        var grps = from p in table.AsEnumerable()
                   group p by p["Column1"].ToString() into g
                   select new
                   {
                       Key = g.Key,
                       Rows = (from q in g
                               select new
                               {
                                   column2 = q["Column2"].ToString(),
                                   column3 = q["Column3"].ToString()
                               }).ToList()
                   };

        foreach (var grp in grps)
        {
            Console.WriteLine(grp.Key);
            foreach (var r in grp.Rows)
            {
                Console.WriteLine(string.Format("{0}\t{1}", r.column2, r.column3));
            }
        }

        Console.Read();
    }
}