如何在一封电子邮件中合并数据

我正在使用Sendmail进行PHP项目。电子邮件发送成功，但将逐个发送。我的编码流程是它将检查数据库，然后如果项目的值小于我设置的值，它将发送电子邮件通知用户。

我想将所有项目合并到一封电子邮件中，以便用户不会收到太多电子邮件来发送相同的通知。我希望你明白我的意思。问题是，我不知道如何使用Sendmail将数据合并到一封电子邮件中。有人可以告诉我应该在哪里更改吗？

这是我的代码：

<?php
include 'MasConnectDB.php';
$sql = "SELECT Item, Available FROM accessories_other";
$result = mysql_query( $sql ) or die( 'Query failed.'.mysql_error() );
while($row = mysql_fetch_array($result)) 
{
$Item = $row['Item'];
$Available = $row['Available'];

 if( $row['Available'] <= 5 ){
    $message2 =  $message3." <div style='margin:30px 0px;'>
                       $Item<br /></div>";
     }
$to       = 'some@email.com';
$subject  = 'Testing sendmail.exe';
$message  = 'The Following Your Product Expired. Product Code:'.$message2;
$headers  = 'From: some@email.com' . "'r'n" .
        'Reply-To: some@email.com' . "'r'n" .
        'MIME-Version: 1.0' . "'r'n" .
        'Content-type: text/html; charset=iso-8859-1' . "'r'n" .
        'X-Mailer: PHP/' . phpversion();
if(mail($to, $subject, $message, $headers))
    echo "Email sent";
else
    echo "Email sending failed";
  }     
?>

编辑：

<?php
include 'MasConnectDB.php';
$sql ="SELECT TC_Status FROM thin_client WHERE TC_Status ='Available'";
$result = mysql_query($sql) or die('Query failed. ' . mysql_error());   
while($row = mysql_fetch_array($result)) {
$TC_STatus = $row['TC_Status'];
if( $result > 5 ){
echo "Thin client is more than 5";
   }
 else 
$to       = 'some@email.com';
$subject  = 'Notification of less on stock';
$message = 'less than 5';
$headers  = 'From: some@email.com' . "'r'n" .
    'MIME-Version: 1.0' . "'r'n" .
    'Content-type: text/html; charset=iso-8859-1' . "'r'n" .
    'X-Mailer: PHP/' . phpversion();
    if(mail($to, $subject, $message, $headers))
echo "Email sent";
  else
echo "Email sending failed";
  } 
?>