This problem should be solved in an earlier stage. Arabic character do not fit in a non-unicode databasetable. That's the real problem.
You should use Unicode tables as well as a Unicode connection to your MySQL database.
Set the default character set of your table to utf8 and make sure the connection to your database is also using this character set:
$conn = mysql_connect($server, $username, $password);
mysql_set_charset("UTF8", $conn);
See also: http://nl3.php.net/manual/en/function.mysql-set-charset.php
Check the character set of your current connection with:
echo mysql_client_encoding($conn);
See also: http://nl3.php.net/manual/en/function.mysql-client-encoding.php
When creating your tables do something like this:
create table user (
// Your table definition
) default charset = UTF8
If you have done these things and add a user which contains arabic character to your table, you will see it is displayed correct. Now the comparison will be easy.
Good luck!