Gridview inside Gridview in ASP.NET C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
/// <summary>
/// Summary description for query
/// </summary>
public class query
{
	public query()
	{
		//
		// TODO: Add constructor logic here
		//
	}
    public static DataSet selectAll()
    {
        DataSet ds = new DataSet();
        string sql = "select * from emp_info";
        ds = Class1.fillDataset(sql);
        return ds;
    }
    public static DataSet selectwithId(long Id)
    {
        DataSet ds = new DataSet();
        string sql = "select * from emp_info where ID='" + Id + "'";
        ds = Class1.fillDataset(sql);
        return ds;
    }
    public static DataTable selectAllTBL()
    {
        DataSet ds = new DataSet();
        string sql = "select * from emp_info";
        ds = Class1.fillDataset(sql);
        DataTable dt = new DataTable();
        dt = ds.Tables[0];
        return dt;
    }
    public static int update(string Id,string name)
    {
        int r=0;
        string sql = "update emp_info set emp_name='" + name + "' where ID='" + Id + "'";
        r = Class1.nonquery(sql);
        return r;

    }

}