title: codeigniter mysql left join include select
body: <p>How to convert the left join include select to codeigniter sql method? Thanks. I just want to know.</p>
  
  <pre><code>SELECT c1.c1_id, c1.c1_name, c2.c2_id, c2.c2_name, c2.c2_type, c2.c2_status, f.f_id, f.f_name, f2.f2_id, f2.f2_name FROM category2 c2 
  LEFT JOIN category1 c1 ON c1.c1_id = c2.c1_id 
  LEFT JOIN (
      SELECT DISTINCT c2_id, f_id, f_name FROM file ORDER BY f_id DESC
  ) f ON f.c2_id = c2.c2_id
  LEFT JOIN (
      SELECT DISTINCT c2_id, f2_id, f2_name FROM file2 ORDER BY f2_id DESC
  ) f2 ON f2.c2_id = c2.c2_id
  WHERE c2.c2_status = 1
  GROUP BY c2.c2_id
  </code></pre>