We will get the duplicate records and insert them into a 
new temp table by using below query:

select * into tmp_Employee
from Employee
having count(distinct *) > 1

Now delete the duplicate records from Employee table:

delete from Employee
having count(distinct *) > 1

Now insert the records from tmp_Employee to Employee table:

insert into Employee
select * from tmp_employee

drop table tmp_employee

with numbered as(select rowno = row_number() over(partition 
by empid order by empid),empname from employee)delete from 
numbered where rowno > 1

select distinct * from table into new_table;

delete table;

select * from new_table into table;

;with empctc(empid,ename,sal,deptid,ranking)
as
(Select empid,ename,sal,deptid,ranking=Dense_rank() over (
partition by empid,ename,sal,deptid order by NEWID() asc) 
from emp
)
delete * from empctc where ranking>1

DELETE FROM emp WHERE ROWID NOT IN(SELECT MAX(ROWID) FROM 
emp GROUP  BY empno)