Delete duplicate rows in mysql and php

How to delete duplicate records in table?
For example :

user_new table - total rows - 45000

duplicate rows - 5150

I have used below this code.It works fine.cheers!!!

<?php 

ini_set("max_execution_time","18800");
$con = mysql_connect("localhost","root","root");
mysql_select_db("testdb",$con);

$query = "SELECT email,count(email),group_concat(user_id) as uid FROM `user_new` group by email having count(email) > 1  ";

$result = mysql_query($query);
$total_rows = mysql_num_rows($result);
$del_ids = array();

if($total_rows>0)
{
  while($row=mysql_fetch_object($result))
  {
    $uid = $row->uid;
$aUid = explode(",",$uid);
array_shift($aUid);
 $rids = array_merge($del_ids,$aUid);
 $del_ids =  $rids;
   }
 //   print_r($del_ids);
   $Sdel_ids = implode(",",$del_ids);
   $del_query = "DELETE FROM user_new where user_id in ($Sdel_ids) ";
   echo $del_query;
   mysql_query($del_query);
}

?>