Exclude posts from main loop based on meta value

Question

I need to modify the main loop (index.php) to exclude posts that have a particular meta value set (via an ACF True / False field).

function exclude_featured_post( $query ) {
    if ( $query->is_home() && $query->is_main_query()) {
        // in case for some reason there's already a meta query set from other plugin
        $meta_query = $query->get('meta_query')? : [];

        // append yours
        $meta_query[] = [
            'key' => 'featured_post',
            'value' => '1',
            'compare' => '!='
        ];

        $query->set('meta_query', $meta_query);
    }
}
add_action( 'pre_get_posts', 'exclude_featured_post' );

This returns no posts. I am thinking I need to merge this with the main query, something like:

global $wp_query;
$merged_args = array_merge( $wp_query->query, $exclude_featured_args );
$query->set('meta_query', $merged_args);

However, this also returns no posts.

Update:

Using 'compare' => 'NOT EXISTS` instead of 'compare' => '!=' seems to return all posts and exclude the meta_query.

function exclude_featured_post( $query ) {
    if ( $query->is_home() && $query->is_main_query()) {
        // in case for some reason there's already a meta query set from other plugin
        $meta_query = $query->get('meta_query')? : [];

        // append yours
        $meta_query[] = [
            'key' => 'featured_post',
            'value' => '1',
            'compare' => 'NOT EXISTS'
        ];

        $query->set('meta_query', $meta_query);

    }
}
add_action( 'pre_get_posts', 'exclude_featured_post' );

From here: https://core.trac.wordpress.org/ticket/18158

Answer 1

Dave, your code seems good except a couple things in it, so please try it:

function exclude_featured_post( $query ) {
    if ( is_front_page() && $query->is_main_query() ) {


        $meta_query = $query->get('meta_query') ? $query->get('meta_query') : array();

        // append yours
        $meta_query[] = array(
            'key' => 'featured_post', // please make sure that key is correct
            'value' => '1',
            'compare' => '!=' // you can also try 'NOT EXISTS' comparison
        );

        $query->set('meta_query', $meta_query);

    }
}
add_action( 'pre_get_posts', 'exclude_featured_post' );

If the above code doesn't work for you, please follow these steps:

1. Make sure that it is running for homepage main query - just try to echo something inside it or so - this step help you to understand if the condition on line 2 is correct.

2. Try to play with more simple params like orderby etc. Check if it works.

3. Test this code for posts which doesn't have another meta_query parameters

4. Try to use meta_key, meta_value and meta_compare params instead of meta_query, example you can find here https://rudrastyh.com/wordpress/meta_query.html

5. And make sure that key feature_post is correct, it hard to believe but among my students it is the most common mistake.