Eliminer dubletter ved hjælp af Oracle LISTAGG-funktionen

Da de linkede svar i kommentaren ikke giver min smag af løsning, sender jeg det alligevel.

Jeg bruger kun table_b med dummy-data for at vise konceptet, kan du nemt tilføje dit join osv.:

with table_b as ( -- dummy data
 select 'name'||mod(level,3) name
        ,mod(level,3) id
   from dual
  connect by level < 10
 union all
 select 'name'||mod(level,2) name
        ,mod(level,3) id
   from dual
  connect by level < 10
)
select id
      ,RTRIM (
              XMLAGG (
                      XMLELEMENT (E,XMLATTRIBUTES (name|| ',' AS "Seg")
                      )
                     ORDER BY name ASC
              ).EXTRACT ('./E[not(@Seg = preceding-sibling::E/@Seg)]/@Seg'),
              ','
             ) AS "Product Name"
       ,LISTAGG(b.name, ',') WITHIN GROUP (ORDER BY b.name) AS "Product Name with dups"
  from table_b b
group by id;

(Idéen er taget fra https://forums.oracle.com/forums/thread.jspa?messageID=9634767&tstart=0#9943367)