WordPress: busca com Custom Fields

gistfile1

//
// By default, WordPress comes with a handy search but it only search in post 
// titles and contents. If you are working on a custom post type, you most 
// probably using custom fields to store its attributes. For example, A 
// Property custom post type would have address, city and state custom fields. 
// You may have used WP_Query object with meta_query setup, But, it does not 
// work. If you do not use “s” attribute, it will overwrite the default search 
// and If you use it, it will not return the expected results. This snippet will 
// use posts_clauses filter to inject the meta query that will combine with the 
// WordPress’s default search parameter.
// 
// http://wpdevsnippets.com/extend-search-include-custom-fields-without-plugin/

function custom_search_where($pieces)
{
    // Filter to select search query.
    if (is_search() && ! is_admin())
    {
 
        global $wpdb;
        $custom_fields = array('field1','field2');
        $keywords      = explode(' ', get_query_var('s'));
        $query         = "";

        foreach ($custom_fields as $field)
        {
             foreach ($keywords as $word)
             {
                 $query .= "(({$wpdb->postmeta}.meta_key = '".$field."')";
                 $query .= " AND ({$wpdb->postmeta}.meta_value  LIKE '%{$word}%')) OR ";
             }
        }
 
        if ( ! empty($query))
        {
            // Add to where clause.
            $pieces['where'] = str_replace("(((wp_posts.post_title LIKE '%", "( {$query} ((wp_posts.post_title LIKE '%", $pieces['where']);
 
            // Add wp_postmeta join if it is not already added.
            if (strpos($pieces['join'],'wp_postmeta') === FALSE)
            {
                $pieces['join'] = $pieces['join'] . " INNER JOIN {$wpdb->postmeta} ON ({$wpdb->posts}.ID = {$wpdb->postmeta}.post_id)";
            }
        }
    }

    return ($pieces);
}

add_filter('posts_clauses', 'custom_search_where', 20, 1);