SQL & PL/SQL

I have written a function(get_cols) which returns the following string (this string is created dynamically from the fuctions depending on the rows of the tables)
the output of the function is;
MAX (CASE WHEN field_code = 'test_pho' THEN VALUE END ) AS test_pho
,MAX (CASE WHEN field_code = 'ESN' THEN VALUE END ) AS ESN
,MAX (CASE WHEN field_code = 'IMSI' THEN VALUE END ) AS IMSI
,MAX (CASE WHEN field_code = 'PHONE_NO' THEN VALUE END ) AS PHONE_NO


What I need to do is to use this as it is in a another select statement like;
(1)
select
empno,
MAX (CASE WHEN field_code = 'test_pho' THEN VALUE END ) AS test_pho
,MAX (CASE WHEN field_code = 'ESN' THEN VALUE END ) AS ESN
,MAX (CASE WHEN field_code = 'IMSI' THEN VALUE END ) AS IMSI
,MAX (CASE WHEN field_code = 'PHONE_NO' THEN VALUE END ) AS PHONE_NO
from my_employee e, my_columns c
where e.emp_no = c.emp_no
and c.emp_no = '100003'
group by empno



function returns the correct output, but when i call the function in the select like below it get it as a whole string and doesn't give the correct output
(2)
select empno, get_cols('100003')
from my_employee e, my_columns c
where e.emp_no = c.emp_no
and c.emp_no = '100003'

how can i get the output of the function to the select as separate line as shown is above(1)
When I get the above output separately and give in the select as above (1) it gives the correct output I want ??

any help please