如何按时间大--》小列出新闻，并且同类别新闻只列出唯一一个 ？？
SELECT DISTINCT classID FROM news ORDER BY addtime DESC,newsID DESC
有错
------解决方案--------------------
select * from news a where not exists
(
select 1 from news where classID=a.classID and addtime> a.addtime
)
order by addtime