Problem: I would like to add a Query Filter that checks whether or not a post has a featured image.
Solution: WordPress stores the featured image in the postmeta table under the key "_thumbnail_id". Using the Views API wpv_filter_query, you could add a check for that meta key to the meta query already generated by the Query Filters. Here's a snippet you can add to functions.php:
[php]
add_filter( 'wpv_filter_query', 'add_filter_by_thumbnail', 10, 3 );
function add_filter_by_thumbnail ( $query, $view_settings, $view_id ) {
if( $view_id == 12345 ) {
$args = array(
'relation' => 'AND',
array(
'key' => '_thumbnail_id',
'compare' => 'EXISTS'
)
);
// add these arguments to your meta query
$query['meta_query'] = isset($query['meta_query']) ? $query['meta_query'] : [];
$query['meta_query'][] = $args;
}
return $query;
}
Replace 12345 with the numeric ID of this View, and you should find that the results of the View all have featured images defined.
Relevant Documentation:
https://toolset.com/documentation/programmer-reference/views-filters/#wpv_filter_query
