public function scopes()
{
    return array(
        'written_time' => array(
            'select' => new CDbExpression('DATE_FORMAT( written, '%H:%i') AS written_time')
        ),
        'written_date' => array(
            'select' => new CDbExpression('DATE_FORMAT( written, '%d.%m.%Y') AS written_date')
        ),
        'teaser' => array(
            'select' => new CDbExpression('IF(LENGTH(content) > 250, LEFT(content, 300), content) AS teaser')
        ),
    );
}

$criteria=new CDbCriteria(array(
        'order' => 'written DESC',
        'scopes' => array(
            'teaser',
            'written_time',
            'written_date',
        ),
        'select' => array(
            'title',
        ),
    ));