Codeigniter LIKE with wildcard(%)
$this->db->like()
automatically adds the %s and escapes the string. So all you need is
$this->db->like('title', $query);
$res = $this->db->get('film');
See the CI documentation for reference: CI 2, CI 3, CI 4
$this->db->like('title', 'match', 'before');
// Produces: WHERE title LIKE '%match'
$this->db->like('title', 'match', 'after');
// Produces: WHERE title LIKE 'match%'
$this->db->like('title', 'match', 'both');
// Produces: WHERE title LIKE '%match%'