title: Binding "not null" in PDO?
body: <p>I recently found out that you can bind null values in PDO:</p>
  
  <pre><code>$stmt = $db-&gt;prepare('SELECT * FROM foo WHERE bar = :bar');
  $stmt-&gt;execute(array(':bar'=&gt;null));
  $foo = $stmt-&gt;fetchAll(PDO::FETCH_OBJ);
  </code></pre>
  
  <p>This would successfully fetch all <code>foo</code> from the database, where the <code>bar</code> column is null.</p>
  
  <p>However, I would now like to do the opposite. I would like to fetch all columns where the <code>bar</code> column is <em>not</em> null.</p>
  
  <p>I am aware I could simply replace <code>bar = :bar</code> with <code>bar IS NOT NULL</code>. However, I would like to avoid that, and instead do it through prepared statements, because I sometimes have to build the query string dynamically and having to do it manually would be a lot of extra work.</p>
  
  <p>Is this possible?</p>