sql - Doctrine Query <timestamp -

i have colum "datetime", this: 2012-06-04 15:40:20.

i want create query in doctrine data of previous time. less 2012-06-04 15:40:20. how can realize in doctrine.

sorry, have no clue.

if understand question correctly, believe syntax just:

$datetime = // timestamp  ->where('t.somefield < ?', date('y-m-d h:i:s', strtotime($datetime))