<?php
function search_article(){
$args = func_get_args();
foreach ($args as $a => $v) if($v === null) unset($args[$a]); else $args[$a] = explode('_', $args[$a])[1];
if (!empty($args)){
	array_unshift($args, "select blablabala where".implode(' and ', array_keys($args)));
	$query = call_user_func_array([$this->db, 'placehold'], $args);
}
else return false;
return $query;
}