secondmax

How do I retrieve the second highest salary of emp?

There is no right or wrong treatment of duplicates, there are only buggy specifications…

There are plenty of ways to do this.

An Oracle 7 approach would be

SELECT MAX(SAL) 
FROM EMP, (
  SELECT MAX(SAL) MAXSAL FROM EMP) 
WHERE SAL>MAXSAL;

Using TOP-n queries I could use

 
SELECT SAL 
FROM (
  SELECT ROWNUM R,SAL FROM (
    SELECT SAL FROM EMP ORDER BY SAL DESC)) 
WHERE R=2;

Using ROW_NUMBER (or RANK or DENSE_RANK), I could use

SELECT SAL 
FROM (
  SELECT ROW_NUMBER() OVER (ORDER BY SAL DESC) R,SAL FROM EMP) 
WHERE R=2;

Another approach would be to create a SecondMax aggregate function, as the following example from the doc
Example 11-12 How to Create and Use a User-Defined Aggregate Function

SELECT SecondMax(sal)
FROM emp;

Ok, if I know I have 14 employees in EMP, retrieving the second highest is way easier 🙂

SELECT PERCENTILE_DISC(2/14) WITHIN GROUP (ORDER BY SAL DESC) 
FROM EMP;

Published by Laurent Schneider

Oracle Certified Master

Join the Conversation

12 Comments

  1. I would not use RANK()..

    SQL> SELECT ENAME, SAL FROM (
    2 SELECT ENAME, SAL FROM EMP ORDER BY SAL DESC)
    3 WHERE ROWNUM < 5; ENAME SAL ---------- --------- KING 5000,00 SCOTT 3000,00 FORD 3000,00 JONES 2975,00 SQL>
    SQL>
    SQL> SELECT SAL
    2 FROM (
    3 SELECT RANK() OVER (ORDER BY SAL DESC) R,SAL FROM EMP)
    4 WHERE R=2;

    SAL
    ---------
    3000,00
    3000,00

    SQL>
    SQL>
    SQL> UPDATE EMP
    2 SET SAL=5000
    3 WHERE ENAME='JONES';

    1 row updated

    SQL>
    SQL>
    SQL> SELECT SAL
    2 FROM (
    3 SELECT RANK() OVER (ORDER BY SAL DESC) R,SAL FROM EMP)
    4 WHERE R=2;

    SAL
    ---------

    SQL>
    SQL> ROLLBACK;

    Rollback complete

  2. My funny solution 😎

    select RTrim(Ltrim(RegExp_Substr(XMLAgg(XMLElement(“dummy”,SAL) order by SAL desc),’…

    [edit]
    last part of query is missing due to < and wordpress, but it could be something like

    RegExp_Substr(XMLAgg(XMLElement("dummy",SAL) order by SAL desc),'\d+',1,2)
    

    [/edit]

  3. Ok, let’s do it with XMLish functions 🙂

    select extractvalue(XMLAgg(XMLElement(SAL,SAL) order by SAL desc),’/SAL[2]’) FROM EMP;

    EXTRACTVALUE(XMLAGG(XMLELEMENT(SAL,SAL)ORDERBYSALDESC),’/SAL[2]’)
    ——————————————————————————–
    3000

  4. Wow!!

    greate solution.
    I did not realize to use extractValue.
    I will study XML.

    In my old posts, my usage of code-tag was wrong.
    My solution was below.


    select RTrim(Ltrim(
    RegExp_Substr(XMLAgg(XMLElement("dummy",SAL)
    order by SAL desc),'>[^>]+<',1,2),'>'),'<') sal from scott.emp;

    SAL
    ----
    3000

Leave a comment

Your email address will not be published.