I have tried the below query:
select empno from ( select empno from emp order by sal desc
try this way it's working 100% SQL> SELECT * FROM STUD;
RNUMBER SNAME MARKS
104 mahesh 85 101 DHANU 20 102 BHARATH 10 100 RAJ 50 103 GOPI 65
SQL> select * from(select MARKS,ROWNUM AS RS from ( select * from stud order by marks desc)) where RS=2;
MARKS RS
65 2
SQL>