Query result: switching rows to columns

If there is a feature available in 9i to help achieve the following I would be grateful if you could point me to it.

Say we have data stored thus:

create table test_results

(person_id		number,
 q_id               test_id number,
 answer             varchar2(30));

person_id is FK to person table
q_id is FK to questions table

Suppose we want to list all the answers given by all candisates for question whose ID is 16,17 or 19

select person_id, q_id, answer
from test_results
where q_id in (16,17,19);

And we get a 3 column result set

person_id       q_id       answer
        1          17          42
        1          19         Yes
        2          16      Always

etc.

I believe it is possible but don't know what to look for to rewrite a query like this so that is will place the different Q_ID values as column headings:

i.e. what we would like to achieve is something like this

person_id      q_id_16_a    q_id_17_a   q_id_19_a   
        1                          42          Yes
        2          Always 

I am sure I recall seeing this kind of question asked before but cannot think what it is called. Of course this could just be wishful thinking!

Thanks for your help.

-- 
jeremy



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   ENVIRONMENT:                                             
   Oracle 9iR2 / Oracle HTTP Server / mod_plsql / Solaris 8 


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