Oracle 10G - Dynamic Decode Function - s it possible - How for CR ?

Question

I will rephrase my question with a better example, then aks my question:-
In the example below, we take the employee name (ename) and the department number (deptno) and display the salary of the employee by their department.
SELECT  * FROM 
(SELECT
  ename,
  sum(decode(deptno,10,sal)) DEPT10,
  sum(decode(deptno,20,sal)) DEPT20,
  sum(decode(deptno,30,sal)) DEPT30,
  sum(decode(deptno,40,sal)) DEPT40
  FROM emp
  GROUP BY ename)
  ORDER BY 1;
The expected result would be as sampled below:- 
ENAME          DEPT10     DEPT20     DEPT30     DEPT40
ADAMS                       1100
ALLEN                                  1600
BLAKE                                  2850
CLARK            2450
..........etc
I would wish to make the Select a dynamic one, with resepect to the departments i.e. I envisage a situation where the Departments increase for example, or are merged for that matter, in which case now my Decode will no longer be accurate. Can I do a Select that has dynamic columns for the departments??

Answer 1

How 'bout using this to feed a cross tab (MS SQL):
select ename, deptno, sum(sal) as salary
from emp
group by ename, deptno
Use ename for your rows, deptno as your columns, and summarize salary for the body of the cross tab.
HTH,
Carl