Query to include if condition in addField How can I include an if condition to my drupal 7 query. This is my query.

$query = "SELECT N_en.nid AS en_nid,     
  IF(N_lan.translate = 1, 'Outdated', 'New') as lan_translated,    
  FROM node N_en
  LEFT JOIN node N_lan ON N_lan.tnid = N_en.nid "


I tried 

$query = db_select('node', 'N_en')-&gt;extend('PagerDefault');
    $query-&gt;addField('N_en', 'nid', 'en_nid');   
    $query-&gt;addField('N_lan', 'translate', 'lan_translated');
    $query-&gt;leftJoin('node', 'N_lan', 'N_en.nid=N_lan.tnid AND N_lan.language=:lang', array(':lang' =&gt; $userLan));


How can I give my if condition for N_lan.translate?
You can add an expression:

...
$query-&gt;addExpression("IF(N_lan.translate = 1, 'Outdated', 'New')", 'lan_translated');
....