title: Multiple meta_key in WP_Query
body: <p>I want to sort my content. I'd like to sort it on two custom meta_keys (the status and the deadline).</p>
  
  <p>So far I've got this:</p>
  
  <pre><code>$mypost = array( 
      'post_type' =&gt; 'customposttype', 
      'order' =&gt; $_GET['order'], //ASC
      'orderby' =&gt; $_GET['orderby'], //meta_value
      'meta_key' =&gt; $_GET['meta_key'], //status
      'meta_value' =&gt; $_GET['meta_value'] //live
  );  
  
  $loop = new WP_Query( $mypost );
  </code></pre>
  
  <p>With the following url I can achieve this query:</p>
  
  <pre><code>&lt;a href="&lt;?php echo add_query_arg(array ('orderby' =&gt; 'meta_value', 'meta_key' =&gt; 'status', 'meta_value' =&gt; 'live', 'order' =&gt; 'ASC'));?&gt;"&gt;Show status=live results&lt;/a&gt;
  </code></pre>
  
  <p>The bottomline is:
  I also want to sort them on 'status=live' and 'deadline'.</p>
  
  <p>The deadline is also a 'meta_key'. Anyone out here know what my query should be like!?</p>