--查询重复的数据

select * from stu where Code in

(

select Code

from  stu

group by Code,Name

having Count(ID) > 1

)

and Name in

(

select Name

from  stu

group by Code,Name

having Count(ID) > 1

)

--用重复的字段分组，不重复的字段Count

--第二种 只能查询出Code这一个字段重复的数据

select * from stu where Code=

 (

  select Code from stu

  group by Code

  having Count(Code)>1

)