title: NULL values in where clause
body: <p>i've got a table "bla" like this:</p>
  
  <pre><code>[id]    [name]    [fk]
  1       test      4
  2       foo       5
  3       bar       NULL
  </code></pre>
  
  <p>if i do the sql query </p>
  
  <pre><code>SELECT * FROM bla WHERE fk &lt;&gt; 4
  </code></pre>
  
  <p>i only get the record with the id 2. i don't get the record with id 3 where fk is null.
  I thought NULL != 4. Seems that this is wrong.</p>
  
  <p>Why is this so?</p>