Wordpress：如何显示特定类别的标签？

Question

I tried many solutions, but not good in my case. Do you have an idea to display "best tags" (most use of last 30 days) from a specific category with function get_terms() of Wordpress ?

<?php $wpdb->show_errors(); ?>
<?php
global $wpdb;
$term_ids = $wpdb->get_col(
"SELECT term_id FROM $wpdb->term_taxonomy
INNER JOIN $wpdb->term_relationships ON $wpdb->term_taxonomy.term_taxonomy_id = $wpdb->term_relationships.term_taxonomy_id
INNER JOIN $wpdb->posts ON $wpdb->posts.ID = $wpdb->term_relationships.object_id
WHERE DATE_SUB(CURDATE(), INTERVAL 30 DAY) <= $wpdb->posts.post_date"
                    );

if(count($term_ids) > 0){
$tags = get_terms(array(
    'orderby' => 'count', 
    'order' => 'DESC', 
    'number' => 8, 
    'include' => $term_ids,
));

foreach ( (array) $tags as $tag ) { ?>
    <li>
        <a href="<?php echo get_tag_link($tag->term_id); ?>" rel="tag" class="text-center">
            <img src="<?php the_field('image', $tag); ?>" class="trend-artist-img">
            <p><?php echo $tag->name ?></p>
        </a>
    </li>
<?php }} ?>

With this code, I have the complete list of the "best tags" but not for a specific category.

The category what I need have the ID : 18.

Thanks!

Answer 1

You can filter by taxonomy by passing the taxonomy to get_terms:

`$tags = get_terms(array( 
        'orderby' => 'count', 
        'order' => 'DESC', 
        'number' => 8, 
        'include' => $term_ids,
        'taxonomy' => 'my_category', // e.g 'post_tag'
    )); 

Or, to filter by a specific category within a taxonomy pass the 'name' to get_terms:

`$tags = get_terms(array( 
        'orderby' => 'count', 
        'order' => 'DESC', 
        'number' => 8, 
        'include' => $term_ids,
        'name' => 'my_category_name', 
    ));

These can be combined. Does this help?

Answer 2

I've re-read your question and I think what you're trying to do is probably not possible with a single query.

The trouble is that both tags and categories are applied to posts rather than to each other, so there's no easy relationship between the two. You could do a new WP_Query for each best tag to check if there are any posts that have both the tag and the category, but that's going to be quite slow and inefficient. Or you could do a WP_Query to get all posts that have that category and ANY of the best tags and then use the results of that query to work out which, if any, of the best tags haven't been used.

Both these options seem more trouble than they're worth to me!