It looks like it would set last_forum_read_at to the oldest unread topic's updated_at value. But then it would fail to include that same topic in the query next time because it used > instead of >=.
It looks like it would set last_forum_read_at to the oldest unread topic's updated_at value. But then it would fail to include that same topic in the query next time because it used > instead of >=.