Arkadaşım, voted alanı TIMESTAMP yada DATETIME tipinde ise bu kadar atraksyona gerek yok.

$tarih = '2014-05-25 00:00:00';
$filtre=" where post_author='$u' and $ay1 and voted<'".$tarih."' and vote>=$a5->a and month(voted)=month(curdate()) and year(voted)=year(curdate()) GROUP BY g.id having count(*)>=$a1->a";