Amant

表结构CREATE TABLE `user1` ( `id` int(11) NOT NULL, `name` varchar(255) DEFAULT NULL, `over` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;CREATE TABLE `user2`

1.重复数据的处理1.利用Group By 和 having从句处理SELECT `name`,COUNT(*) FROM `user1` GROUP BY `name` HAVING COUNT(*) > 1;2.删除重复数据，对于相同数据保留ID最大的DELETE a FROM user1 a JOIN(SELECT `name`,COUNT(*),MAX(id) AS id FROM user

http://blog.youkuaiyun.com/zhuqinfeng/article/details/73198779?locationNum=11&fps=1--以前的写法-必须借助row_number()函数来获取行的序列号Select *from ( select ROW_NUMBER() over(order by name asc) as __te...