在SQL中存在count()函数，它可以计算行数。在你的例子中，我们想要帖子的数量，所以我们可以使用COUNT(posts.id)，如下所示：

<?php
$author = get_query_var('author');
$categories = $wpdb->get_results("
    SELECT DISTINCT(terms.term_id) as ID, terms.name, terms.slug, tax.description, count(posts.id) AS `count`
    FROM $wpdb->posts as posts
    LEFT JOIN $wpdb->term_relationships as relationships ON posts.ID = relationships.object_ID
    LEFT JOIN $wpdb->term_taxonomy as tax ON relationships.term_taxonomy_id = tax.term_taxonomy_id
    LEFT JOIN $wpdb->terms as terms ON tax.term_id = terms.term_id
    WHERE posts.post_status = 'publish' AND
        posts.post_author = '$author' AND
        tax.taxonomy = 'category'
    ORDER BY terms.name ASC
");
?>
<ul>
    <?php foreach($categories as $category) : ?>
    <li>
        <a href="<?php echo get_category_link( $category->ID ); ?>" title="<?php echo $category->name ?>">
            <?php echo $category->name.'('.$category->count.') '.$category->description; ?>
        </a>
    </li>
    <?php endforeach; ?>
</ul>

您会注意到，我使用了和别名来重命名count列（否则，它的名称将是count(posts.id)--实际上并不实用）。我还删除了WHERE中的1=1，因为它在这里没有用。

我想通了。。必须运行分离的SELECT函数：一个用于获取类别列表，然后该循环中的另一个函数用于计算类别中有多少个条目。我更喜欢把这两个循环合二为一，但这对我来说是可行的。

<?php

// This will get us a list of the categories that our Author has published in
$author = get_query_var('author');
$categories = $wpdb->get_results("

SELECT DISTINCT(terms.term_id) as ID, terms.name, terms.slug, tax.description
FROM $wpdb->posts as posts
LEFT JOIN $wpdb->term_relationships as relationships ON posts.ID = relationships.object_ID
LEFT JOIN $wpdb->term_taxonomy as tax ON relationships.term_taxonomy_id = tax.term_taxonomy_id
LEFT JOIN $wpdb->terms as terms ON tax.term_id = terms.term_id
WHERE posts.post_status = 'publish' AND
    posts.post_author = '$author' AND
    tax.taxonomy = 'category' 
ORDER BY terms.name ASC
");

// This loop picks up categories
foreach($categories as $category) : 

$catid = $category->ID;

// Now, inside the loop, we need to count how many posts that the Author has published.
$counter = "SELECT COUNT(*)
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->term_taxonomy.term_id = $catid
AND $wpdb->term_taxonomy.taxonomy = 'category'
AND $wpdb->posts.post_status = 'publish'
AND post_author = '$author'
";

$user_count = $wpdb->get_var($counter);

echo '<div class="archive_author">' . $category->name . '<br/><span class="subcounter">' . $user_count . ' posts</span></div>';

endforeach; 

?>

我通常使用这个插件（http://wordpress.org/plugins/author-profiles/）在侧边栏中显示。我想这段代码会帮助任何人

<?php

  global $wpdb;
  $table_users.=$wpdb->base_prefix;
  $table_users.="users";
  $table_posts.=$wpdb->base_prefix;
  $table_posts.="posts";

  $fetch_authordata="SELECT count(p.post_author) as post1,c.id, c.user_login, c.display_name,c.user_nicename, c.user_email, c.user_url, c.user_registered FROM {$table_users} as c , {$table_posts} as p {$where} and p.post_type = 'post' AND p.post_status = 'publish' and c.id=p.post_author GROUP BY p.post_author order by post1 DESC limit {$author_numbers}  ";

  $dispaly_authordata = (array) $wpdb->get_results("{$fetch_authordata}", object);

  foreach ( $dispaly_authordata as $author ) {
  $user = get_userdata($author->id);

  echo 'Display Name: '.$user->display_name;
  echo 'Post Count: '.$post_count = get_usernumposts($user->ID);

  }
 ?>