group by with order by in codeigniter code example

Example 1: codeigniter order by

$this->db->from($this->table_name);
$this->db->order_by("name", "asc");
$query = $this->db->get(); 
return $query->result();

Example 2: codeigniter where order by

$this->db->select('ae_users.employee_id, ae_users.emp_name, ae_users.emp_name2, ae_users.emp_name3');
		$this->db->from('ae_users');                
		$this->db->where_in('ae_users.employee_id',$employee_ids);
                $this->db->_protect_identifiers = FALSE; // stop CI adding backticks
                $order = sprintf('FIELD(ae_users.employee_id, %s)', implode(', ', $employee_ids));
                $this->db->order_by($order);
                $this->db->_protect_identifiers = TRUE; 
		$query =$this->db->get();
               // echo '<pre>'; print_r($this->db->last_query());exit;
		if ($query->num_rows()) {
			return $query->result_array();
		} else {
			return 0;
		}