SqlConnection con = new SqlConnection(ConnectionString);
 
      String query = "select * from Employee, Department";
 
      SqlCommand cmd = new SqlCommand(query,con);
 
      SqlDataReader dr;
 
      con.Open();
 
      dr = cmd.ExecuteReader();
 
      GridView1.DataSource = dr;
 
      GridView1.DataBind();
      con.Close();