<?php if(isset($_REQUEST['datepost']))
{
$date = date('m/d/Y',strtotime($_POST['date']));
$res=mysql_query("SELECT * FROM `wp_posts` WHERE DATE_FORMAT(post_date, '%m/%d/%Y' ) = $date AND post_type = 'post' ORDER BY post_date DESC");
$pageposts=mysql_fetch_array($res);
exit();
}
?>
Forneça o valor real para a coluna post_date como DATE_FORMAT(post_date, '%m/%d/%Y' ) =$date
