Wordpress查询具有音频附件和/或自定义字段

been trying several things but to no avail... Searched, maybe not good enough though!

I have posts that either have an uploaded audio file AND/OR has a Soundcloud link (which is a custom field).

Now I would like to return posts that either have a Soundcloud link, an uploaded file or both.

$arguments = array(              
    'post_parent'    => get_the_ID(),
    'post_type'      => 'attachment',
    'post_mime_type' => 'audio',
    'order'          => 'DES',
    'orderby'        => 'parent',
    'numberposts'    => -1,
); 

$attachments = get_posts($args);

Is what I currently use. This of course, returns only posts that have an audio attachment.

I've been trying the 'relation' and 'meta_query' options, but failed. Maybe I'm doing something wrong. I think I could do this with 2 different get_posts(); in an if/else statement. But I want to avoid repeating code.

Hope that is clear enough.