SELECT `m` . `meta_id` , `m` . `comment_id` , `m` . `meta_key` FROM `wp_commentmeta` AS `m` LEFT JOIN `wp_comments` AS `c` USING ( `comment_id` ) WHERE `c` . `comment_id` IS NULL AND `m` . `meta_id` > ? ORDER BY `m` . `meta_id` LIMIT ? 