pdo ile şu şekilde hallettim. herkese teşekkürler



date_default_timezone_set('Europe/Istanbul');
$date = date("d M Y H:i:s",strtotime('-4 days'));
$sonvakit = strtotime($date);
echo $sonvakit;

$sql = "DELETE from posts where date_created < $sonvakit";

if ($conn->query($sql) === TRUE) {
echo "Record deleted successfully";
} else {
echo "Error deleting record: " . $conn->error;
}