Вот запрос:
Код: Выделить всё
SELECT
posts.date, posts.author AS pauthor, topics.*,
CASE
WHEN posts.date > topics.date THEN posts.date
WHEN topics.date > posts.date THEN topics.date
END AS ldate
FROM
posts, topics
WHERE
topics.id = posts.topic_id
AND forum_id = ?
ORDER BY
ldate DESC
LIMIT 1
Подробнее здесь: https://stackoverflow.com/questions/243 ... -the-forum
Мобильная версия