Display one row only

Question

This query
SELECT
SCRATTR_ATTR_CODE
from scrattr_TEST,scbcrse_TEST
where
SUBSTR(scbcrse_subj_code,1,3)  = SUBSTR(scrattr_subj_code,1,3)
and SUBSTR(scbcrse_crse_numb,1,4)  = SUBSTR(scrattr_crse_numb,1,4)Returns this
SCRATTR_ATTR_CODE
A
INS
MCSR How I can make to return someting like A INS MCSR in one row there is a row for every code
hERE is some code to create the tables and insert the data
CREATE TABLE SCRATTR_test
  SCRATTR_SUBJ_CODE      VARCHAR2(4 CHAR)       NOT NULL,
  SCRATTR_CRSE_NUMB      VARCHAR2(5 CHAR)       NOT NULL,
  SCRATTR_EFF_TERM       VARCHAR2(6 CHAR)       NOT NULL,
  SCRATTR_ATTR_CODE      VARCHAR2(4 CHAR)
  CREATE TABLE SCBCRSE_test
  SCBCRSE_SUBJ_CODE              VARCHAR2(4 CHAR) NOT NULL,
  SCBCRSE_CRSE_NUMB              VARCHAR2(5 CHAR) NOT NULL,
  SCBCRSE_EFF_TERM               VARCHAR2(6 CHAR)
insert into SCRATTR_test (SCRATTR_SUBJ_CODE,SCRATTR_CRSE_NUMB,SCRATTR_EFF_TERM,SCRATTR_ATTR_CODE) select 'BIO','2210','201320',' A' from dual;
insert into SCRATTR_test (SCRATTR_SUBJ_CODE,SCRATTR_CRSE_NUMB,SCRATTR_EFF_TERM,SCRATTR_ATTR_CODE) select 'BIO','2210','201320','INS' from dual;
insert into SCRATTR_test (SCRATTR_SUBJ_CODE,SCRATTR_CRSE_NUMB,SCRATTR_EFF_TERM,SCRATTR_ATTR_CODE) select 'BIO','2210','201320','MCSR' from dual;
COMMIT;
INSERT INTO  SCBCRSE_test(SCBCRSE_SUBJ_CODE,SCBCRSE_CRSE_NUMB,SCBCRSE_EFF_TERM) SELECT  'BIOL','2210','201320' FROM DUAL
COMMIT; Thank you

Answer 1

Based on your testcase, on 11.2 you could just:
SQL> select listagg(a.SCRATTR_ATTR_CODE, ' ') within group (order by rownum)
  2  from   scrattr_TEST a
  3  ,      scbcrse_TEST b
  4  where  SUBSTR(b.scbcrse_subj_code,1,3)  = SUBSTR(a.scrattr_subj_code,1,3)
  5  and    SUBSTR(b.scbcrse_crse_numb,1,4)  = SUBSTR(a.scrattr_crse_numb,1,4);
LISTAGG(A.SCRATTR_ATTR_CODE,'')WITHINGROUP(ORDERBYROWNUM)
A INS MCSR