请尝试以下代码：

WARNING: THIS IS JUST PSEUDOCODE!

$entries = $wpdb->get_results("SELECT * FROM wp_posts WHERE post_type IN (\'post\', \'page\')");

foreach($entries as $entry)
{
    $post_id = $entry->ID;
    $comment_count = $wpdb->get_var("SELECT COUNT(*) AS comment_cnt FROM wp_comments WHERE comment_post_ID = \'$post_id\' AND comment_approved = \'1\'");
    $wpdb->query("UPDATE wp_posts SET comment_count = \'$comment_count\' WHERE ID = \'$post_id\'");
}