/**
* @return Questionnaire
*/
protected function get_questionnaires()
{
$person = new Person();
$person->get_by_id(auth_get_id());
$questionnaire_answers = new Questionnaire_answer();
$questionnaire_answers->select_func('MAX', '@answer_number', 'max_answer');
$questionnaire_answers->group_by('person_id');
$questionnaire_answers->where_related($person);
$questionnaire_answers->where_related_questionnaire('id', '${parent}.id');
$questonnaires = new Questionnaire();
$questonnaires->select('*');
$questonnaires->select_subquery($questionnaire_answers, 'max_answer_number');
$questonnaires->where('published', 1);
$questonnaires->get_iterated();
return $questonnaires;
}
