how using mysql CAST in db_select

Question

I want to try doing Mysql Casting in my query by db_select but face to error,

$q=db_select('node','n');
          $q->join('field_data_field_cinema_type', 'fct', 'fct.entity_id = n.nid');
          $q->condition('n.type',array('movie'),'IN');
          $q->condition('fct.field_cinema_type_tid',11095,'=');
          $q->condition('cast(n.nid AS SIGNED )',11517,'>'); // also $q->condition('cast(n.nid AS SIGNED INTEGER )',11517,'>');
          $q->fields('n',array('nid','type'));
          ym((string)$q);
     $res= $q->orderBy('nid')->execute()->rowCount();

and query string

SELECT n.nid AS nid, n.type AS type FROM {node} n INNER JOIN {field_data_field_cinema_type} fct ON fct.entity_id = n.nid WHERE (n.type IN (:db_condition_placeholder_0)) AND (fct.field_cinema_type_tid = :db_condition_placeholder_1) AND (castn.nidASSIGNEDINTEGER > :db_condition_placeholder_2)

My question is how can I use Mysql Casting in db_select?Is that supported in db_select or I should use db_query on EntityQuery ?

Answer 1

You can use the where() method for a SelectQuery:

...
$q->where('CAST(n.nid AS SIGNED) > :nid', array(':nid' => 11517));
...

So the choice is yours which type of query to use.