Fwd: Hmm.. I got NULL here. Why?

My PHP Source
=============
<?php
    include('../../tilkobling.php');
    $sql = "SELECT kg_pa_lager FROM dynamit WHERE valgt_lager =
'$valgt_lager' AND varenr = '$varenr'";
    $resultat = mysql_query($sql, $tilkobling) or die(mysql_error());
    while($rad = mysql_fetch_array($resultat)){
        $kg_pa_lager = $rad['kg_pa_lager'];
        echo "$kg_pa_lager";
        }
        var_dump($sql);
        echo "<br />";
        var_dump($kg_pa_lager);
    ?>

My var_dump() value;
==================
string(84) "SELECT kg_pa_lager FROM dynamit WHERE valgt_lager = 'Tengs' AND
varenr = 'EDY22X180'"
NULL

My Database table:
===============
mysql> SELECT * FROM dynamit;
+------------+-------------+---------------+--------+-------+----------+------------+-------------+
| leverandor | valgt_lager | type          | dim_mm | un_nr | varenavn |
varenr     | kg_pa_lager |
+------------+-------------+---------------+--------+-------+----------+------------+-------------+
| Orica      | Tengs       | Papirpatroner | 22x180 | 0081  | Dynamit  |
EDY22X180K | 100         |
| Orica      | Tengs       | Papirpatroner | 25x180 | 0081  | Dynamit  |
EDY25X180  | 100         |
| Orica      | Tengs       | Plastpølse   | 45x540 | 0081  | Dynamit  |
EDY45X540  | 100         |
+------------+-------------+---------------+--------+-------+----------+------------+-------------+
3 rows in set (0.00 sec)

mysql>

The Problem:
==========
If I do this:
$sql = "SELECT kg_pa_lager FROM dynamit WHERE valgt_lager = '$valgt_lager'";
I got 100100100 for kg_pa_lager

But if I do this:
$sql = "SELECT kg_pa_lager FROM dynamit WHERE valgt_lager = '$valgt_lager'
AND varenr = '$varenr'";
I got NULL.

Look at varenr = EDY22X180 in the select where and that it is in the table
under varenr.
But why is kg_pa_lager NULL?

This is strange to me but I guess you know why?
Thanks for your advice.

Karl

I got the solution. I had forget to write "K" at end of the serial number.
Now it is OK.
Karl