update in codeigniter

public function updateNewsCategory($id,$image){

$sql=$this->db->query("UPDATE `news_category` SET

`name`='".$this->db->escape_str($this->input->post('name'))."',
`mobile`='".$this->db->escape_str($this->input->post('mobile'))."',
`detail`='".$this->db->escape_str($this->input->post('detail'))."',
    `created_dt`=Now(),
`isactive`='".$this->db->escape_str($this->input->post('isactive'))."'
WHERE id='".(int)$id."'");


return $sql;
}