Hi folks,

One the more frequently asked questions is how to "sum" up strings by
virtue of concatenating them in an aggregate function.
Her eis a rather simpel solution that may be worth sharing (you'll be
teh judge):
DROP TABLE T;
CREATE TABLE T(servername VARCHAR(15), volume VARCHAR(10), capacity
VARCHAR(10));
INSERT INTO T VALUES
('ServerA', 'Vol1', '5GB'),
('ServerB', 'Vol1', '5GB'),
('ServerC', 'Vol2', '11GB'),
('ServerD', 'Vol2', '11GB'),
('ServerE', 'Vol3', '20GB');

SELECT Volume, Capacity,
       VARCHAR(REPLACE(REPLACE(VARCHAR(XML2CLOB(XMLAGG(XMLELEMENT(NAME
a, ServerName)
                                        ORDER BY ServerName)), 60),
                              '<A>', ''),
               '</A>', ','), 60) AS ServerList
  FROM T GROUP BY Volume, Capacity;

VOLUME     CAPACITY   SERVERLIST
---------- ---------- ------------------
Vol1       5GB        ServerA,ServerB,
Vol2       11GB       ServerC,ServerD,
Vol3       20GB       ServerE,

  3 record(s) selected.