Posts with no views are excluded. Why?

It is a technical limitation. The meta_key will only be created for every post published after the plugin has been activated.

There is nothing I can do here.

I understand. Thanks.

Internally, I guess there’s an INNER JOIN involved? How can we see the generated query? Not sure if a LEFT JOIN would solve this at once. But I’m considering using a plain MySQL query to retrieve results (on my custom view).

Well, I solved it with something like this:

function set_default_views_metakey($post_ID){
    add_post_meta($post_ID, 'views', 0, true);
    return $post_ID; // not sure if needed
}

add_action('wp_insert_post','set_default_views_metakey');

It works. New posts now has zero as default views count.

And this will correct the error in existing posts:

$args = array(
    //'post_type' => 'post',
    'meta_query' => array(
        'relation' => 'OR',
        array(
            'key' => 'views',
            'value' => 'bogus', // you have to pass a value
            'compare' => 'NOT EXISTS'
        ),
        array(
            'key' => 'views',
            'value' => ''
        )
    ),
    'fields' => 'ids'
  );

  // perform the query to get back an array of ids
  $posts = new WP_Query( $args );

  foreach ( $posts->posts as $id ) {
      add_post_meta($id, 'views', 0, true);
  }

ref: https://wordpress.stackexchange.com/questions/121165/save-default-value-for-empty-or-missing-post-meta

@gperez-tl: thanks for sharing, this will work if you have a few post, but if your post tables is large, it will probably time out.

But this is a good answer, to be honest I did not thought of this. I am going to pin this topic.

Hi Lester,

Have you updated the plugin with above issue?