Hur sammanfogar man text från flera rader till en enda textsträng i Oracle-servern?

Har du testat detta?

select end_date,
       listagg(CLOSE_DATE, ',') within group (order by CLOSE_DATE DESC) as close_dates,
       listagg(id, ',') within group (order by id) as ids
from TBL_S_PLCLOSEDATE
where D_END = date '2018-05-18'
group by end_date;