合区并筛选
create table uses{
id int(11) auto_increment,
useid varchar(30) not null,
server varhcar(10) not null,
date datetime not null
}
Alter table user add unique(useid,server);
insert into uses values(0,'wowo',1,'2011-01-12 00:00:00');
insert into uses values(0,'wowo',2,'2011-01-15 00:00:00');
insert into uses values(0,'aa','2011-01-15 00:00:00');
insert into uses values(0,'aa','2011-01-12 00:00:00');
我想把2各区的数据合并,但是2区和1区数据可能相同,所以触犯唯一约束,之后还要筛选2各合并后只留下时间比较早的那个帐号,另外一个删除