title: Cakephp complex find "NOT IN"
body: <p>I have two tables called calendar_colour and user,</p>
  
  <pre><code>calendar_colour
  (
     colour_id int primary key,
     colour varchar(15)
  )
  
  
  user
  (
     id int primary key,
     name varchar(30),
     color int,
     foreign key(color) references calendar_colour(colour_id)
  )
  </code></pre>
  
  <p>In the add function of the user I have to choose a colour from a dropdown box. But I want to populate the dropdown using the colours that are not already taken by previous users. I tried using a find command but it seems to be wrong.</p>
  
  <pre><code>$curColours = $this-&gt;EventType-&gt;query('select color from event_types');
  
  $this-&gt;set('colours', $this-&gt;EventType-&gt;CalendarColour-&gt;find('list',array('conditions'=&gt;array('NOT',array('CalendarColour.colour_id' =&gt; $curColours)))));
  </code></pre>
  
  <p>I use the array <code>$colours</code> to populate the dropdown box. What is the correct way to write the find command that finds the colours that are not used by any users.</p>
  
  <p>Thanks.</p>