PIVOT Rows to Column using XML

I want to get output of multiple rows into single variable seperated by comma. How can I achieve that. There is also requirement of using dynamic sql as table and column will be known at runtime only.

Here is the example :



select rtrim(dbms_xmlgen.getxmltype('select empno '','' e from EMP WHERE DEPTNO = '&p_deptno).extract('//text()'),',') x
from dual;

X
--------------
7782,7839,7934