multiset intersect

-- SetupCREATE TABLE filter_test_master
    (nr                             NUMBER NOT NULL,
    name                           VARCHAR2(32 CHAR) NOT NULL)
/
CREATE TABLE filter_test_detail
    (nr                             NUMBER NOT NULL,
    name                           VARCHAR2(32 CHAR) NOT NULL,
    master_nr                      NUMBER)
/
Create Or Replace
TYPE Numbercollection AS TABLE OF NUMBER
/
CREATE OR REPLACE VIEW filter_test_v1 (
   nr,
   name,
   detail_nrs )
AS
select nr
     , name
     , cast( multiset ( select nr from filter_test_detail b where b.master_nr = a.nr )
       as NumberCollection) detail_nrs
from filter_test_master a
/
insert into filter_test_master (nr,name) values(1,'Master1')
/
insert into filter_test_master (nr,name) values(2,'Master2')