title: Multiple conditions for db_update
body: <p>In Drupal 7 simple updates work like this:</p>
  
  <pre><code>$num_updated = db_update('joke')
  -&gt;fields(array(
  'punchline' =&gt; 'Take my wife please!',
  ))
  -&gt;condition('nid', 3, '&gt;=')
  -&gt;execute();
  </code></pre>
  
  <p>But what if I have multiple conditions( say nid >=3 and uid >=2). Writing something like:</p>
  
  <pre><code>$num_updated = db_update('joke')
  -&gt;fields(array(
  'punchline' =&gt; 'Take my wife please!',
  ))
  -&gt;condition('nid', 3, '&gt;=')
  -&gt;condition('uid', 2, '&gt;=')
  -&gt;execute();
  </code></pre>
  
  <p>does not seem to work. Any ideas?</p>