select id, max(ltrim(sys_connect_by_path(gred,' , '),' , ')) as mygred from (select b.KJ19SIJIL||b.KJ19KOD as id, b.KJ19GRED as gred, row_number() over(partition by b.KJ19SIJIL||b.KJ19KOD order by b.KJ19GRED) as myrow from kj19setara b) start with myrow = 1 connect by prior myrow = myrow -1 and prior id = id group by id order by 1;