title: Compare two dates post_date and post_modified in Wordpress
body: <p>I want filter posts which post_modified > post_date (posts modified).</p>
  
  <p>I query on database with </p>
  
  <pre><code>"SELECT id, post_title, post_date, post_modified 
  FROM wp_posts 
  WHERE post_type = 'post' AND post_status = 'publish' AND DATE(post_date) &lt;&gt; DATE(post_modified) 
  ORDER BY post_modified "
  </code></pre>
  
  <p>the output is right.</p>
  
  <p>But if I use <code>WP_query</code> for this: </p>
  
  <pre><code>PostQueryExample = new WP_Query(array('orderby' =&gt; 'modified', 'order' =&gt; 'DESC', 'post_type'=&gt;'post','post_status' =&gt; 'publish', 'no_found_rows' =&gt; 1, 'ignore_sticky_posts' =&gt; 1,                           
          'date_query' =&gt; array(
                  array(
                      'column' =&gt; 'post_date',
                      'compare' =&gt; '&lt;',
                  ),
                  array(
                      'column' =&gt; 'post_modified',
                      'compare' =&gt; '&gt;',,
                  ))))
  </code></pre>
  
  <p>But shows the wrong output, please help me</p>