Generatin query with joshcam extension

Question

I am running this query in phpmyadmin and it works fine. But on running it in joshcam's MySQLi Database class it gets error
Query :

SELECT
   t.id, t.name From tags t, file_tag_relation ft,
WHERE 
   t.id = ft.tag_id
AND
   ft.file_id = 35

PHP code :

$db->where('t.id = ft.tag_id'); 
$db->where('ft.file_id = 35'); 
$a = $db->get('tags t , tile_tag_relation ft', null, '*');