Wordpress WP_Query compare not working?

Question

There are my arguments for my custom WP_Query.

$args = array(
    'post_type' => 'post',
    'posts_per_page' => '9',
    'name'=>'Products',
    'compare'=>'LIKE'
);
$the_query = new WP_Query( $args );
echo $the_query->request;

which returns the following query:

SELECT wp_posts.* 
FROM wp_posts 
WHERE 1=1 
    AND wp_posts.post_name = 'products' 
    AND wp_posts.post_type = 'post' 
ORDER BY wp_posts.post_date DESC 

As I can see, this is not creating a LIKE query like I'd like to have one.

Answer 1

What you're trying to achieve is a LIKE query. But you're using the compare arguments that are only present for meta_query arguments. You need to utilize a filter like the following:

add_filter( 'posts_where', 'wpse120358TitleLike', 10, 2 );
function wpse120358TitleLike( $where, &$wp_query )
{
    global $wpdb;
    if (
        'post' === $wp_query->get( 'post_type' )
        AND $wp_query->get( 'name' )
        // add further restriction arguments here:
        // AND ...
        )
    {
        $where .= $wpdb->prepare(
            ' AND %s LIKE %s',
            "{$wpdb->posts}.post_title",
            '%'.like_escape( $wp_query->get( 'name' ) ).'%'
        );
    }

    return $where;
}

Note that this is not a tested script. It's meant as a guideline that can be built upon.