FULL OUTER JOIN으로 하시면 되네요~

WITH A AS
(
    SELECT '2019' AS YEAR, '2' AS HAKGI, '홍길동' AS NAME, '1231' AS HAKBEON, '성적우수A' AS JANGHAK FROM DUAL UNION ALL
    SELECT '2019' AS YEAR, '2' AS HAKGI, '임꺽정' AS NAME, '1232' AS HAKBEON, '성적우수A' AS JANGHAK FROM DUAL UNION ALL
    SELECT '2019' AS YEAR, '2' AS HAKGI, '이순신' AS NAME, '1233' AS HAKBEON, '성적우수A' AS JANGHAK FROM DUAL 
),
B AS
(
    SELECT '2020' AS YEAR, '1' AS HAKGI, '임꺽정' AS NAME, '1232' AS HAKBEON, '성적우수A' AS JANGHAK FROM DUAL UNION ALL
    SELECT '2020' AS YEAR, '1' AS HAKGI, '이순신' AS NAME, '1233' AS HAKBEON, '성적우수B' AS JANGHAK FROM DUAL UNION ALL
    SELECT '2020' AS YEAR, '1' AS HAKGI, '세종대왕' AS NAME, '1236' AS HAKBEON, '성적우수C' AS JANGHAK FROM DUAL 
)
SELECT *
  FROM A FULL OUTER JOIN B ON  A.HAKBEON = B.HAKBEON
 ORDER BY A.HAKBEON;

YEAR H NAME      HAKB JANGHAK       YEAR H NAME         HAKB JANGHAK
---- - --------- ---- ------------- ---- - ------------ ---- -------------
2019 2 홍길동    1231 성적우수A
2019 2 임꺽정    1232 성적우수A     2020 1 임꺽정       1232 성적우수A
2019 2 이순신    1233 성적우수A     2020 1 이순신       1233 성적우수B
                                    2020 1 세종대왕     1236 성적우수C

테이블이 두개인 것처럼 질문하셨지만?
실제로는 하나의 테이블을 조건을 달리하여 두번 조회한것일 것 같습니다.
이렇게 두번 나누어 조회하여 다시 조인하는 방식은 좋지 않습니다.
그냥 한번에 조회하면 조인 안해도 됩니다.
 

WITH t AS
(
SELECT '2019' year, '2' hakgi, '홍길동' name, '1231' hakbeon, '성적우수a' janghak FROM dual
UNION ALL SELECT '2019', '2', '임꺽정'  , '1232', '성적우수A' FROM dual
UNION ALL SELECT '2019', '2', '이순신'  , '1233', '성적우수A' FROM dual 
UNION ALL SELECT '2020', '1', '임꺽정'  , '1232', '성적우수A' FROM dual
UNION ALL SELECT '2020', '1', '이순신'  , '1233', '성적우수B' FROM dual
UNION ALL SELECT '2020', '1', '세종대왕', '1236', '성적우수C' FROM dual
)
SELECT hakbeon
     , name
     , MIN(CASE WHEN (year, hakgi) IN (('2019', '2')) THEN janghak END) janghak_2019_2
     , MIN(CASE WHEN (year, hakgi) IN (('2020', '1')) THEN janghak END) janghak_2020_1
  FROM t
 WHERE (year, hakgi) IN (('2019', '2'), ('2020', '1'))
 GROUP BY hakbeon, name
 ORDER BY hakbeon
;