php - Codeigniter ActiveRecord: join backticking

Question

I've a simple question: how can I use CodeIgniter's ActiveRecord join function? I want this:

LEFT JOIN cimke ON (mk_terem.id_kicsoda=5 AND mk_terem.id_target=cimke.id_cimke)
LEFT JOIN tanar ON (mk_terem.id_kicsoda=1 AND mk_terem.id_target=tanar.id_tanar)

But if I use $this->db->join(cimke,"mk_terem.id_kicsoda=5 AND mk_terem.id_target=cimke.id_cimke"), the value 5 will be between backticks.

How can I do this?

UPDATE

What I want? If mk_terem.id_kicsoda is 1, then I want tanar.nev and when mk_terem.id_kicsoda is 5, I want cimke.nev.

The full SQL-query:

SELECT
terem.nev terem_nev,
elem_tipus.nev tipus_nev,
(IFNULL(cimke.nev,tanar.nev)) nev
FROM mk_terem
LEFT JOIN terem ON mk_terem.id_terem=terem.id_terem
LEFT JOIN cimke ON (mk_terem.id_kicsoda=5 AND mk_terem.id_target=cimke.id_cimke)
LEFT JOIN tanar ON (mk_terem.id_kicsoda=1 AND mk_terem.id_target=tanar.id_tanar)
LEFT JOIN elem_tipus ON (mk_terem.id_kicsoda=elem_tipus.id_kicsoda)

Answer 1

Only a simple workaround, ugly, not elegant, but it works in this case:

$original_reserved = $this->db->_reserved_identifiers;
$this->db->_reserved_identifiers[] = 5;
$this->db->_reserved_identifiers[] = 1;
// or any other values
$this->db->join('with critical values and conditions');
// some db-stuff
$this->db->_reserved_identifiers = $original_reserved;

If anybody knows better please show it!