Kohana 3 ORM compares 2 columns in where clause

Question

I need to generate query like that :

SELECT * FROM `table1` WHERE `date1` < `date2`

I can't find how to compare 2 columns in kohana ORM. Here date2 is considered as text.

$foo = ORM::factory('model1')->where('date1','<','date2');

How can I write this line ?

Thanks!

More info:

I use this for the moment:

$query = DB::query(Database::SELECT, "SELECT id FROM table1 WHERE `date1` < `date2`");
$result = $query->execute();

$foo = array();
foreach ($result as $r) {
    $foo[] = ORM::factory("model1", $r['id']);
}

Answer 1

If you don't want Kohana to modify the string, as it would with the 3rd argument in the DB where function, you can use the DB::expr() function which will leave what you pass unmodified. So with your example, you could use

$foo = ORM::factory('model1')->where('date1','<',DB::expr('date2'));