Finding nth highest salary

Question

Hi guys , I am trying to find the nth highest salary
using the below query , is there any case in which the below query can fail
select
* from (
select
distinct rownum rn,salary from emp_mgr order by rownum) t where t.rn=3

Answer 1

chris227 wrote:
Sory, may be i am blind, dont see it yet.
Doesnt the Nth high paid employee earns the Nth highest salary?
No. Multiple employees can earn same salary. Look at EMP table:
SQL> select ename,sal from emp order by sal desc;
ENAME             SAL
KING             5000
FORD             3000
SCOTT            3000
JONES            2975
BLAKE            2850
CLARK            2450
ALLEN            1600
TURNER           1500
MILLER           1300
WARD             1250
MARTIN           1250
ENAME             SAL
ADAMS            1100
JAMES             950
SMITH             800
Highest salary 5000. Second highest salary is 3000. Third highest salary is 2975. Now look what NTH_VALUE returns:
SQL> select distinct sal
  2    from (select nth_value(sal,&n) over(order by sal desc) sal from emp)
  3  /
Enter value for n: 1
old   2:   from (select nth_value(sal,&n) over(order by sal desc) sal from emp)
new   2:   from (select nth_value(sal,1) over(order by sal desc) sal from emp)
       SAL
      5000
SQL> /
Enter value for n: 2
old   2:   from (select nth_value(sal,&n) over(order by sal desc) sal from emp)
new   2:   from (select nth_value(sal,2) over(order by sal desc) sal from emp)
       SAL
      3000
SQL> /
Enter value for n: 3
old   2:   from (select nth_value(sal,&n) over(order by sal desc) sal from emp)
new   2:   from (select nth_value(sal,3) over(order by sal desc) sal from emp)
       SAL
      3000
SQL> /
Enter value for n: 4
old   2:   from (select nth_value(sal,&n) over(order by sal desc) sal from emp)
new   2:   from (select nth_value(sal,4) over(order by sal desc) sal from emp)
       SAL
      2975
SQL>
SY.