题目:
找出教师表(Teacher)中姓名(Name)重复的数据,然后删除多余重复记录,只留字段ID最小的那个。
delete from Teacher
where Name in (select Name from Teacher group by Name Having Count(*)>1)
and ID not in (select Min(ID) from Teacher group by Name Having Count(*)>1);
另外网上资料参考(讲的很好):
http://www.jb51.net/article/93269.htm