Query Posts with Custom Taxonomy from a Custom Post Type

Question

I've been bashing my head against my desk over this for the past day or so...I have created a custom post type called 'advertisement' and a custom taxonomy within that post type called 'group'. I've created a bunch of different posts and assigned them to the various groups that I have created, but the problem is when I try to query the posts for my custom taxonomy, it comes up empty.

When I try to query a regular post with the default category it works fine, so I'm beginning to think it has something to do with the way I have setup my taxonomies. I've already tried resetting permalinks, but to no luck.

Here is what I have so far:

If anyone could shed some light on where I might have gone wrong, that would be wonderful.

Thanks!

/*-----------------------------------------------------------------------------------*/
/*  Initialize the post type
/*-----------------------------------------------------------------------------------*/

/**
 * Custom Post Type: Advertisements
 *
 * @package WordPress
 * @subpackage ExportWise
 */


/* Register custom taxonomies on the 'init' hook. */
add_action( 'init', 'register_taxonomy_groups' );

function register_taxonomy_groups() {

    $labels = array( 
        'name'                          => __( 'Groups',                            'bd' ),
        'singular_name'                 => __( 'Group',                             'bd' ),
        'search_items'                  => __( 'Search Groups',                     'bd' ),
        'popular_items'                 => __( 'Popular Groups',                    'bd' ),
        'all_items'                     => __( 'All Groups',                        'bd' ),
        'parent_item'                   => __( 'Parent Group',                      'bd' ),
        'parent_item_colon'             => __( 'Parent Group:',                     'bd' ),
        'edit_item'                     => __( 'Edit Group',                        'bd' ),
        'update_item'                   => __( 'Update Group',                      'bd' ),
        'add_new_item'                  => __( 'Add New Group',                     'bd' ),
        'new_item_name'                 => __( 'New Group',                         'bd' ),
        'separate_items_with_commas'    => __( 'Separate groups with commas',       'bd' ),
        'add_or_remove_items'           => __( 'Add or remove groups',              'bd' ),
        'choose_from_most_used'         => __( 'Choose from the most used groups',  'bd' ),
        'menu_name'                     => __( 'Groups',                            'bd' ),
    );

    $args = array( 
        'labels'                        => $labels,
        'public'                        => true,
        'show_in_nav_menus'             => false,
        'show_ui'                       => true,
        'show_tagcloud'                 => false,
        'show_admin_column'             => true,
        'hierarchical'                  => true,

        'rewrite'                       => true,
        'query_var'                     => true
    );

    register_taxonomy( 'group', array('advertisement'), $args );
}


/* Register custom post types on the 'init' hook. */
add_action( 'init', 'my_register_post_types', 20 );

/**
 * Registers post types.
 *
 * @since  0.1.0
 * @access public
 * @return void
 */
function my_register_post_types() {

    /* Set up the arguments for the post type. */
    $args = array(

        'public'              => true,
        'publicly_queryable'  => true,
        'exclude_from_search' => true,
        'show_in_nav_menus'   => false,
        'show_ui'             => true,
        'show_in_menu'        => true,
        'show_in_admin_bar'   => true,
        'menu_position'       => 20,
        'menu_icon'           => 'dashicons-chart-line',
        'can_export'          => true,
        'delete_with_user'    => false,
        'hierarchical'        => true,
        'has_archive'         => false,
        'query_var'           => true,
        'rewrite' => array(
            'with_front' => false,
            'pages'      => true,
            'feeds'      => true,
        ),

        'supports' => array( 'title' ),
        'taxonomies' => array( 'group' ),

        'labels' => array(
            'name'               => __( 'Advertisements',                   'bd' ),
            'singular_name'      => __( 'Advertisement',                    'bd' ),
            'menu_name'          => __( 'Advertisements',                   'bd' ),
            'name_admin_bar'     => __( 'Advertisements',                   'bd' ),
            'add_new'            => __( 'Add New',                          'bd' ),
            'add_new_item'       => __( 'Add New Advertisement',            'bd' ),
            'edit_item'          => __( 'Edit Advertisement',               'bd' ),
            'new_item'           => __( 'New Advertisement',                'bd' ),
            'view_item'          => __( 'View Advertisement',               'bd' ),
            'search_items'       => __( 'Search Advertisements',            'bd' ),
            'not_found'          => __( 'No advertisements found',          'bd' ),
            'not_found_in_trash' => __( 'No advertisements found in trash', 'bd' ),
            'all_items'          => __( 'All Advertisements',               'bd' ),

            'parent_item'        => __( 'Parent Advertisement',             'bd' ),
            'parent_item_colon'  => __( 'Parent Advertisement:',            'bd' ),
        )
    );

    /* Register the post type. */
    register_post_type(
        'advertisement',
        $args
    );
}


/*-----------------------------------------------------------------------------------*/
/*  Add custom taxonomies to the post type
/*-----------------------------------------------------------------------------------*/

function create_my_taxonomies() {
    register_taxonomy(
        'group',
        'advertisement',
        array(
            'labels' => array(
            'name' => 'Groups',
            'add_new_item' => 'Add New Group',
            'new_item_name' => "New Group"
        ),
        'show_ui' => true,
        'show_tagcloud' => false,
        'hierarchical' => true,
        'public' => true
        )
    );
}
add_action( 'init', 'create_my_taxonomies', 0 );

/*-----------------------------------------------------------------------------------*/
/*  Query the CPT for Posts from a specific custom taxonomy
/*-----------------------------------------------------------------------------------*/

    // If on an Article, display random advertisements
    if ( is_single() ) {
        $posts_per_page = 1;
        $orderby = 'rand';

    // Otherwise display the latest advertisement
    } else {
        $posts_per_page = 1;
        $orderby = 'date';  
    }

    $args = array(
        'post_type' => 'advertisement',
        'tax_query' => array(
            array(
                'taxonomy' => 'group', 
                'terms' => array( 'homepage' ),
                'field' => 'slug',
            ),
        ),
        'posts_per_page'    => $posts_per_page,
        'orderby'           => $orderby, 
    );

    $query_advertisements = new WP_Query( $args );

    //echo $query_advertisements->request; ?>

    <?php if ( $query_advertisements->have_posts() ) : ?>
        <div class="widget widget_ads_320" id="marketing_box">
            <div class="ads320">
                <div class="ads-content">
                    <?php 
                        while ( $query_advertisements->have_posts() ) : $query_advertisements->the_post();
                            $adv_image = getUploadedImageSrc();
                            $adv_url = get_post_meta( get_the_ID(), 'adv_url', true ); 
                            echo '<a href="' . $adv_url . '"><img src="' . $adv_image . '" alt="' . get_the_title() . '" /></a>';
                        endwhile; 
                        wp_reset_postdata();
                    ?>
                </div>
            </div>
        </div>
    <?php else : ?>
        <p>Error retrieving advertisements! Please try again later.<br><br></p>
    <?php endif; ?>

Answer 1

It looks like you forgot to set the field parameter to search for slugs:

$args = array(
    'post_type' => 'advertisement',
    'tax_query' => array(
        array(
            'taxonomy' => 'group', 
            'terms' => array( 'homepage' ),
            'field' => 'slug',
        )
    )
);

Notice that the taxonomy query uses the term_id as the default search field.

I would also use another variable than $wp_query to store the result of the secondary query.

I hope this solves your problem ;-)