Assistance required converting MySQL function to PDO - mysql

Question

I'm currently converting MySQL to PDO, I'm unsure if I wrote this function correctly,I'm also unsure of how to use sqlfiddle, so I resort to Stackoverflow.
If correct, anything to better the current code?
MySQL example :
PUBLIC FUNCTION Insert_Update($_iD, $update, $uploads){
$update = mysql_real_escape_string($update);
$time = time();
$_iP = $_SERVER['REMOTE_ADDR'];
$query = mysql_query("SELECT post_iD,message FROM `Posts` WHERE uid_fk='$_iD' ORDER by post_iD DESC LIMIT 1") or die(mysql_error());
$result = mysql_fetch_array($query);
if ($update!=$result['message']) {
$uploads_array = explode(',',$uploads);
$uploads = implode(',',array_unique($uploads_array));
$query = mysql_query("INSERT INTO `Posts` (message, uid_fk, _iP,created,uploads) VALUES (N'$update', '$_iD', '$_iP','$time','$uploads')") or die(mysql_error());
$newquery = mysql_query("SELECT M.post_iD, M.uid_fk, M.message, M.created, U._iUsername FROM Posts M, users U where M.uid_fk=U._iD and M.uid_fk='$_iD' order by M.post_iD desc limit 1 ");
$result = mysql_fetch_array($newquery);
return $result;
} else {
return false;
}
}
PDO Example:
PUBLIC FUNCTION Insert_Update($_iD, $update, $uploads){
$sth = $this->db->prepare("SELECT post_iD,message FROM `Posts` WHERE uid_fk = :id ORDER by post_iD DESC LIMIT 1")
$sth->execute(array('id' => $_iD));
$result = $sth->FetchAll(PDO::FETCH_ASSOC);
if ( $update!=$result['message'] ){
$uploads_array = explode(',',$uploads);
$uploads = implode(',',array_unique($uploads_array));
$sth = $this->db->prepare("INSERT INTO Posts (message, uid_fk, _iP,created,uploads) VALUES ( :update, :id, :ip, :time, :uploads)")
$sth->bindValue(':update', $update);
$sth->bindValue(':id', $_iD);
$sth->bindValue(':ip', $_SERVER['REMOTE_ADDR']);
$sth->bindValue(':time', time());
$sth->bindValue(':uploads', $uploads);
$sth->execute()
$sth = $this->db->prepare("
SELECT M.post_iD, M.uid_fk, M.message, M.created, U._iUsername
FROM Posts M, users U
WHERE M.uid_fk=U._iD
AND M.uid_fk = :id
ORDER by M.post_iD DESC LIMIT 1 ");
$sth->execute(array(':id' => $_iD));
$result = $sth->FetchAll(PDO::FETCH_ASSOC);
return $result;
} else {
return false;
}
}