php loop into sql query

[ahs10]

i'd like to turn this php loop into an sql query.  can someone help me do that please?

<?php

$all = mysql_query("SELECT product_number, order_number, tracking_number FROM dhl92") or die(mysql_error());

while ($row = mysql_fetch_array($all)) {
     $matches = myql_query("SELECT id FROM dhl92 WHERE product_number = '" . $row['product_number'] . "' AND order_number = '" . $row['order_number'] . "' AND tracking_number = '" . $row['tracking_number'] . "'") or die(mysql_error());
     $count = mysql_num_rows($matches);
     for ($i = 1; $i < $count; $i++) {
          $result = mysql_result($matches, $i);
          $remove = mysql_query("DELETE FROM dhl92 WHERE id = '" . $result . "'") or die(mysql_error());
     }
}

?>

 

this will remove all but one row that have the same product_number, order_number, and tracking_number.  any help is much appreciated.  thanks!

[fenway]

Why the outer query?

 

And why not use the second query ($matches) but just replace "SELECT id" with "DELETE"?