$ank_rating=$post['id_user'];
$post ???
$user['id_user']
Поверь вначале сам запрос вносит ли он значение в таблицу
mysql_query("UPDATE `users` SET `rating`+0.02 WHERE `id` = 1;");
mysql_query("UPDATE `users` SET `rating`+0.02 WHERE `id` = 1;");
$ank_rating=$post['id_user'];
mysql_query("UPDATE `users` SET `rating` = '". ($user['rating']+0.02) ."' WHERE `id` = '". $ank_rating ."'");
mysql_query("UPDATE `users` SET `rating`+0.02 WHERE `id` = '". $user['id_user'] ."'");
if (mysql_result(mysql_query("SELECT COUNT(`id`) FROM `mchat` WHERE `id_user` = '". $user['id'] ."'"), 0) == 3)
if (mysql_result(mysql_query("SELECT COUNT(`id`) FROM `mchat` WHERE `id_user` = '". $user['id'] ."'"), 0) == 3)
$sms = mysql_fetch_row(mysql_query("select count(*) from `mchat` where `id_user` = '". $user['id'] ."'"));
if($sms[0] >= 3){
твой код
}