Mohon suhu bantu buat id reminder ke php + mysql

Assalam,.. sudah sejauh mana usahanya untuk mencobakan?
bisa di share kendalanya dimana dan sekalian script yg bermasalah agar bisa kita bantu untuk solusinya?
 

Assalam,..
Oh ya saya kurang mengirimkan scriptnya ya. Saya kirim ya kekurangannya.
 
 
<?php
 
//penomoran dari satu
$awal=0;
include('system/conf/koneksi.php');
$perintah="SELECT * FROM data_karyawan ORDER by id DESC";
$nom="$awal"; //awal 0 nanti ditambah satu
$nom2=sprintf("%s",$perintah,$nom); //eksekusi $perintah dan $nom
$query=@mysql_query($nom2,$koneksi);
$jumlah_karyawan=mysql_num_rows($query);
 
?>
 
<!-- CEGAH BY PASS PERHALAMAN -->
<?php 
if(!isset($_SESSION['admin'])){
    echo '<script language="javascript">alert
    ("Anda harus login dulu!");document.location="login.php?page=masuk";</script>';
}
?>
 
<div class="row">
                <div class="col-lg-12">
                <h2 class="page-header">Status Pengajuan Karyawan</h2>
                <div class="panel panel-default">
                        <div class="panel-heading">
                            Data Karyawan Status</div>
                 <!-- /.panel-heading -->
                        <div class="panel-body">
                            <table width="100%" class="table table-striped table-bordered table-hover" id="dataTables-example">
                                <thead>
 
                                <tr>
                                        <th colspan="2">JUMLAH KARYAWAN </th>
                                        <th colspan="2"><?php echo $jumlah_karyawan; ?></th>
                                        <th colspan="6"><a href="print-pengajuanbaru.php" target="_blank"><i class="fa fa-print fa-fw" alt="print" title="print semua karyawan"></i></a>
 
                                    </tr>
 
                                    <tr>
                                        <th>NIK</th>
                                        <th>Nama</th>
                                        <th>Tanggal MCU Akhir</th>
                                        <th>Pengajuan ke Berau Coal</th>
                                        <th>Expired ID Card Baru</th>
                                        <th>Jatuh tempo(60 hari)</th>
                                         <th>Selisih</th>
                                        <th>Aksi</th>
 
 
                                    </tr>
                                </thead>
                                <tbody>
<?php //ngambil data dan memecahnya ke array 
include('system/conf/koneksi.php');
$perintah="SELECT * FROM data_karyawan ORDER by id DESC";
//Penggunaan fungsi dateiif untuk menghitung selisih dan jatuh tempo
 $query = mysql_query("SELECT * ,DATE_ADD(expired_idcardbaru, INTERVAL 90 DAY) as jatuh_tempo, DATEDIFF(DATE_ADD(tgl_pembelian, INTERVAL 90 DAY), CURDATE()) as selisih FROM data_karyawan"); while ($data = mysql_fetch_array($query)) 
{
	$result = mysql_query($data);
if($result === FALSE) {
    die(mysql_error()); // TODO: better error handling
}
	while ($row = mysql_fetch_array($result)) 
 
?>
 
 
 
                                    <tr class="odd gradeX">
 
<td><?php echo $data['id'];?></td>
<td><?php echo $data['nama'];?></td>
<td><?php echo $data['tgl_mcu_akhir'];?></td>
<td><?php echo $data['pengajuanke_bc'];?></td>
<td><?php echo $data['expired_idcardbaru'];?></td>
<td><?php echo $data2['jatuh_tempo'];?></td>
<td><?php echo $data2['selisih'];?></td>
 
<td>
  <a href="detail-karyawan.php?detail=<?php echo $data['id']?>"><i  class="fa fa-eye fa-fw" alt="detail" title="View Detail"></i></a>
  <a href="edit-karyawan.php?edit=<?php echo $data['id']?>"><i class="fa fa-edit fa-fw" alt="edit" title="Edit"></i></a>
  <a href="print-pengajuanbaru.php?printpdf=<?php echo $data['id']?>" target="_blank"><i class="fa fa-print fa-fw" alt="print" title="print"></i></a>
  <a href="del.php?del=<?php echo $data['id']?>"><i class="fa fa-trash-o fa-fw" alt="delete" title="Delete"></i></a>
</td>
 
 
                                    </tr>
 <?php $no+=1; } ?>
                              </tbody>
                          </table>
                      </div>
                                    <div class="panel-footer">
                          Karyawan PT. BUMA</div>
                                    </div>
 
                                    </div>
                                    </div>
 
 
            <!-- /.row -->
<!-- ApliMak (Aplikasi Management Karyawan)
 ********************************************
   ********************************************
 -->
 

Assalam,.. intinya cuma menghitung selisih 2 tanggal saja, begini caranya :
<?php 
$date1='2018-02-08';
$date2='2019-02-08';
$datetime1 = new DateTime($date1);
$datetime2 = new DateTime($date2);
$difference = $datetime1->diff($datetime2);
echo $difference->days." Hari";
 
if ($difference->days<=60){
  // Notifikasi jatuh tempo insert/kirim ke karyawan terkait
}
?>