$user = Flight::db()->select('tb_user', ['user_id', 'name']);
$new_arr = [];
$num_u = 1;
foreach($user as $key => $val){
	$name = mb_substr($val['name'], 0, 1);
	if(isset($new_arr[$name])){
		$num_u = $new_arr[$name]['num_u'];
		$num_u ++;
		// $new_arr[$name]['names'][] = $val['name'];
		$new_arr[$name]['num_u'] = $num_u;
	}else{
		// $new_arr[$name]['names'][] = $val['name'];
		$new_arr[$name]['num_u'] = $num_u;
	}
}
$num_us = array_column($new_arr,'num_u');
array_multisort($num_us,SORT_DESC,$new_arr);

var_dump($new_arr);
die();