Query all published post AND attachment with specific mime type

Question

I need to add only specific attachments (PDF) to the query along with other CPT. But when I add mime type value to the query any other post type get filtered out.

Here is the query args

$args = [
    'post_type' => ['any', 'attachment'],
    'post_status' => ['publish', 'inherit'],
    'post_mime_type' => ['application/pdf'],
    'posts_per_page' => 10
];

How do I get other post types with attachments of specific mime type? (only pdf in this case)

Answer 1

First of all if any is used for post_type field there can not be any other value given in array like in the question. Below is the modified args

$args = [
    'post_type' => array_values(get_post_types(['public' => true])),
    'post_status' => ['publish', 'inherit'],
    'posts_per_page' => 10
];

Use posts_where filter

add_filter('posts_where', 'add_search_mime_types');
$query = new WP_Query( $args );
remove_filter('posts_where', 'add_search_mime_types');


function add_search_mime_types($where){
    $where .= ' AND post_mime_type IN("application/pdf","") ';
    return $where;
}

The empty string on the SQL query to include post types other then attachment.