I have a custom taxonomy called coauthor. On the edit.php screen, I am trying filter and only show posts authored by the current user OR posts coauthored by the current user. I can get the posts authored by the current user:

function get_authored_posts($query) {
    global $user_ID;
    $query->set('author',  $user_ID);
    return $query;
add_filter('pre_get_posts', 'get_authored_posts');

I can also get the posts coauthored by the current user:

function get_coauthored_posts($query) {
    global $user_ID;
    $user = get_userdata($user_ID);
    $query->set('taxonomy', 'coauthor');
    $query->set('term', $user->user_login);
    return $query;
add_filter('pre_get_posts', 'get_coauthored_posts');

I believe the results yield posts authored AND coauthored by the current user. I am looking for posts authored OR coauthored by the current user. I am expecting the results from the first and the results from the second to be displayed.

Note: To clarify, coauthors are stored as terms as part of the coauthor taxonomy. The term is the user_login value.

== EDIT ==

I am currently storing the author as a coauthor. I feel like this is a "work around" for a better solution. How/Can I use a direct query (ignoring the WP_Query object) and return that from the pre_get_posts filter?

  • 2
    It's beyond the scope of WP_Query's argument support, you'll have to look at filtering the SQL and replace parts to make the author and taxonomy OR related(ie. either or, instead of having an AND relation). Have a look through the query code in wp-includes/query.php, there are numerous filters/actions available.
    – t31os
    Nov 29, 2011 at 14:29

2 Answers 2


When I implemented something similar for a company that needed multiple authors, we did much the same with an author taxonomy. But in that case, we didn't use the original author field at all.

Basically, it's not possible to create a standard WP_Query with author=X OR coauthor=Y using standard methods. You'd have to resort to direct SQL fiddling, which is problematic and prone to accidental breakage.

Using the coauthor taxonomy exclusively, however, it's fairly trivial to make a tax_query which has coauthor IN (X,Y) very simply.

So no, it's not really a workaround, it's actually the best way to do it. The posts table is entirely geared towards a single author. If you need multiple authors, then special-casing one of them into that post_author field is actually the real WTF here, because why bother? It's more sensible to use the taxonomy instead and allow a fully multi-connected coauthor system.

  • I wrote this system with @otto. Definitely the way to go. Dec 12, 2011 at 17:31
  • 2
    That said, we actually used postmeta to achieve the same result. Author IDs were individual meta_values and each had the same coauthor meta_key. On save, the meta_values were all blown away and re-saved with the new author IDs. This makes querying easy and prevents the need to come up with terms like user_login. Dec 12, 2011 at 17:32

I am not sure if you can easily add OR queries to the $query object.

It seems possible when querying on meta info, eg:

 $args = array(
    'post_type' => 'product',
    'meta_query' => array(
        'relation' => 'OR',
            'key' => 'color',
            'value' => 'blue',
            'compare' => 'NOT LIKE'
            'key' => 'price',
            'value' => array( 20, 100 ),
            'type' => 'numeric',
            'compare' => 'BETWEEN'
 $query = new WP_Query( $args );

Note the 'relation' parameter. This is taken from towards the bottom of this codex page: http://codex.wordpress.org/Class_Reference/WP_Query

An alternative would be to store the author as a coauthor as well.

  • Thank you. I am aware of the OR relation for meta queries and I am currently storing the author as a coauthor. I just feel like this is a "work around" for a better solution.
    – v0idless
    Nov 29, 2011 at 14:32

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