[Scottish] php and my sql

[Ismail Murat Dilek]

Hi,
I ve created a mysql database. Basically user fills  the form then  hits 
submit button and  all data posted to mysql database.This part works fine.
Next time user return the page enters their email address and hits 
submit button. my php script
check if email address exist in our database if exist takes user to 
download page, if not exist takes them to registration page.
Some strange reason this comparasing is not working properly. it works 
for some email addresses,
e.g. my email address olive@zoom.co.uk is registered in mysql database 
so script should take to download page but it is taking me registration 
page instead
any ideas
<?
//Author: Ismail Murat Dilek

require("conn.php");
/// ========================================================
// following part read values of entered details and prepares them for 
mysql data input format

$email = $HTTP_POST_VARS["email"];
///========================================================


$query ="Select email from details"; // selects email field from details 
table
$result = mysql_query($query); //executes sql select query
$num_result = mysql_num_rows($result);
/* searches database for email, if email dosent exist writes details to
database,then redirects user to download page
*/
for ($i=0; $i<$num_result; $i++)
{
    $row= mysql_fetch_array($result);
    $eml = stripslashes($row[email]);
    $email = trim($email);
    $eml = trim($eml);
    $eq = strcmp($email,$eml);
    if ($eq != 0)
    {
    header("Location:register.php");
   
    }
    else
    {
    header("Location:download.php");
    }
   
   
   
}//end for

?>