mysql比较恶心的一个delete in操作
mysql中

  
后面的select 加个where怎么养？delete from sns_hits where id not in (select id from sns_hits)  

好神奇哦，作者用这个语句来干什么啊
从这个表里删除不在这个表里的元素？ 4 楼 仅此而已 2012-08-21 起个别名就好！

DELETE FROM t_tag
WHERE id NOT IN (SELECT * FROM (SELECT MAX(t .id) AS id FROM t_tag t GROUP BY tagname)t)