Getting data from multiple rows into one column

select deptno,rtrim(xmlagg(xmlelement(e,ename||',')).extract('//text()'),',') ename from scott.emp group by deptno;


DATA :
Deptno Ename
10 A
10 B
10 C
20 D
20 E
20 F


OUTPUT:
Deptno Ename
10 A,B,C
20 D,E,F