WordPress帖子按类别排序，然后按日期排序

Question

I have no idea how to do this, this is what needs to happen. Posts need to display in this order:

1. Posts in Category 1 (that's the name, not the ID though I can use the ID it's 22)
2. Posts in Category 2 (id is 25)
3. the rest of the posts

Each of these should be in order from newest to oldest and the ones in the third tier should not include any duplicates from the first two categories.

I tried using a UNION but I could never get the order correct, then found out UNION only supports ONE 'ORDER BY' at the end, which jumbles them all up, defeating the purpose.

Here's the other issue. This has to work with $wp_pagenavi, and the current method just dumps them all out on one page.

Here's what I currently have:

<div id="content" class="post right">
<?php
    $query = "(SELECT * FROM $wpdb->posts LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) WHERE $wpdb->posts.post_status = 'publish' AND $wpdb->term_taxonomy.taxonomy = 'category' AND $wpdb->term_taxonomy.term_id = 22 ORDER BY post_date DESC) UNION ";
    $query .= "(SELECT * FROM $wpdb->posts LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) WHERE $wpdb->posts.post_status = 'publish' AND $wpdb->term_taxonomy.taxonomy = 'category' AND $wpdb->term_taxonomy.term_id = 25 ORDER BY post_date DESC)";
    error_log($query);
    $pageposts = $wpdb->get_results($query, OBJECT);

?>  
    <?php if ($pageposts) : ?>
    <?php global $post; ?>
    <?php foreach ($pageposts as $post) : ?>
    <?php setup_postdata($post); ?>
            <div class="article">
                <p class="post-title"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></p>
                            <?php the_time('F jS, Y') ?><br />
                            <?php the_excerpt(); ?>
            </div>
        <?php if (  $wp_query->max_num_pages > 1 ) : ?>
            <div class="navigation">
                    <?php wp_pagenavi(); ?>
            </div>
        <?php endif; ?>
    <?php endforeach; ?>
    <?php else : ?>
        <div id="post-0" class="post error404 not-found">
            <h1>Not Found</h1>

            <div class="entry">
                <?php  
                    if ( is_category() ) { // If this is a category archive
                        printf("<p>Sorry, but there aren't any posts in the %s category yet.</p>", single_cat_title('',false));
                    } else if ( is_date() ) { // If this is a date archive
                        echo("<p>Sorry, but there aren't any posts with this date.</p>");
                    } else if ( is_author() ) { // If this is a category archive
                        $userdata = get_userdatabylogin(get_query_var('author_name'));
                        printf("<p>Sorry, but there aren't any posts by %s yet.</p>", $userdata->display_name);
                    } else if ( is_search() ) {
                        echo("<p>No posts found. Try a different search?</p>");
                    } else {
                        echo("<p>No posts found.</p>");
                    }
                ?>
                <?php get_search_form(); ?>
            </div>
        </div>

Answer 1

From your question it sounds like you want all the published posts, not just the ones in the categories you mentioned.

Therefore, you need WHERE criteria to select them all. I don't think you want a UNION of the ones in just in those categories.

If you use an ORDER BY clause like this, you should get them in the order you're mentioning.

ORDER BY $wpdb->term_taxonomy.term_id = 22 DESC, 
         $wpdb->term_taxonomy.term_id = 25 DESC,
         $wpdb->posts.post_date DESC

The first two terms evaluate to either true 1 or false 0 . Ordering them DESC puts the trues first. The last term puts everything in descending order of data.