title: Intriguing sql query (not in select)
body: <p>I have the following sql query in mysql:</p>
  
  <pre><code>SELECT * 
  FROM _t_test
  WHERE pret NOT 
  IN ( 2.6700, 2.6560, 1.8200 ) 
  </code></pre>
  
  <p>I would expect the rows with the value 1.8200 not to be shown, yet I still get them.
  Am I missing something?
  The field "pret" is double(16,4).</p>