Dynamically selecting column names in report builder ???

Question

Dear members,
I have a requirement in which the user dynamically selects the tables column names. Like suppose take DEPT table. My query would be
select &P Report from dept;
so if the user selects DNAME then i would get the dname values and so on... This is fine but if one gives the value for the lexical parameter as DEPTNO,DNAME then i should get two columns in my report output. The select statement then becomes
select DEPTNO,DNAME Report from dept;
But i am not able to do this in report builder(6i). If i use just one value for the parameter then i get the o/p but if i use more than one (eg: DEPTNO,DNAME) then its giving an error.when i run this query through toad or sql plus then i am getting the desired o/p but wher as in report builder i am not able to get the o/p.
My report triggers are :
Before Parameter form :
:P := NULL;
After parameter Form :
function AfterPForm return boolean is
begin
IF :P = 'DNAME,DEPTNO' THEN
:P := ' DNAME,DEPTNO ' ;
ELSE
     :P := NULL;
     END IF;
return (TRUE);
end;
Your comments and suggestions are welcomed.
thanks
regards
sandeep

Answer 1

Number of columns can not be changed at run time. If your data model has three columns, lexical parameter should pass 3 values. If you have query like this in data model:
select &p_1 from table
Whatevere you have as initial value in user parameter p_1, data model captures that info.