如何在codeigniter框架php中制作这个sql语句？

 $this->db->select('count("id") as c');
$this->db->where('valid',1);
$this->db->where('sticky',2);
$result = $this->db->get('products');

   $this->db->select('COUNT(id) AS c');
   $this->db->from('products');
   $this->db->where('valid =', 1);
   $this->db->where('sticky =', 2);
   $query= $this->db->get();

$where['valid'] = 1;
$where['sticky'] = 2;

$db->select('count("id") as c');
$query = $db->get_where('products',$where);