SQL Server - TOP Clause

TOP

                * Introduced in SQLSERVER 2005 

                * It specifies the first 'n' rows of the query result that are to be retrieved

Top with Delete 

                             Delete top(4) from emp

Top with Update

                             Update top(3) dept set sal=sal*0.9 where deptno=10

Top with Percent 

                             Select top (5) percent ename,sal from emp

                             Select top 5 percent * from emp

Top with Order By 

                            Select top 6 * from emp order by ename desc

Write a query to find duplicate records

Select deptno,ename ,count(*) from emp group by deptno,ename having count(*)>1

                                               

Write a query to delete duplicate rows?

Delete TOP 1 from T1 where a=10 and b=20 and c=30