private function getStatFor($field, $value)
{
$request = new Statistic();
return $request->query("SELECT sum(point) point FROM activities_students\n LEFT JOIN activitys ON activities_students.activity_id = activitys.id\n LEFT JOIN students ON activities_students.student_id = students.id\n where `{$field}` = '{$value}'\nGROUP BY student_id\nORDER BY point DESC");
}
