sql query joining three tables
===

I have to select `category name,description,id` from the `tbl_ticket_categories` from that selected `id` I have to find the `user_id` from the `tbl_ticket_repliers` and from that `user_id` I have to find the `username` from the `tbl_users`.

Finally selected attributes should be `category_name, description and username` . 
What I am doing my view is :-

        function editCategory($site_referers_id) {
            $this->db->select('tbl_ticket_categories.category_name,tbl_ticket_categories.description,tbl_users.username,tbl_ticket_repliers.user_id');
            $this->db->where('site_referers_id',$site_referers_id);
            $this->db->join('tbl_ticket_repliers','tbl_ticket_repliers.category_id = tbl_ticket_categories.id');
            $this->db->join('tbl_users','tbl_users.id = tbl_ticket_repliers.user_id');
            return $this->db->get('tbl_ticket_categories');
        }


In my view, when I am doing `<?php var_dump($categories); ?>`
it showing :-

    object(CI_DB_mysql_result)[32]
      public 'conn_id' => resource(43, mysql link persistent)
      public 'result_id' => resource(81, mysql result)
      public 'result_array' => 
        array
          empty
      public 'result_object' => 
        array
          empty
      public 'custom_result_object' => 
        array
          empty
      public 'current_row' => int 0
      public 'num_rows' => int 1
      public 'row_data' => null

How to do this query :(