SELECT `p`.`title`, `p`.`text`, `t`.`tag`
FROM (
SELECT `title` FROM `posts` WHERE ... LIMIT 10
) AS `p`
LEFT JOIN `post_tag` AS `pt` ON `pt`.`post_id` = `p`.`id`
LEFT JOIN `tags` AS `t` ON `t`.`id` = `pt`.`tag_id`
ORDER BY `p`.`title`, `t`.`tag`
