SQL query to delete duplicate rows from same table?

Question

suppose there is a employee table containing columns name, id and salary having 2 or more than two rows with same values in all three rows...then how to write a query to delete duplicate rows..

Answer 1

Here is a nice way if you use Sql Server

with duplicates as
(select * ,ROW_NUMBER() over(

      partition by id,name, salary
      order by id,name, salary) rownum
from Person)
delete from duplicates where rownum > 1

Answer 2

assuming ID is the primary key:

delete P
from Person P right outer join
(
   select name, min(id) as id
   from Person
   group by name
) unique_people
on P.id = unique_people.id
where P.id is NULL