outer join test

SELECT X.USER_SEQ, Y.SCORE1, Z.SCORE2

FROM

(

    SELECT 'A' USER_SEQ FROM DUAL UNION ALL

    SELECT 'B' USER_SEQ FROM DUAL UNION ALL

    SELECT 'C' USER_SEQ FROM DUAL UNION ALL

    SELECT 'D' USER_SEQ FROM DUAL UNION ALL

    SELECT 'E' USER_SEQ FROM DUAL

) X

, (

    SELECT 'A' USER_SEQ, '10' SCORE1 FROM DUAL UNION ALL

    SELECT 'B' USER_SEQ, '20' SCORE1 FROM DUAL UNION ALL

    SELECT 'E' USER_SEQ, '30' SCORE1 FROM DUAL

) Y

, (

    SELECT 'B' USER_SEQ, '100' SCORE2 FROM DUAL UNION ALL

    SELECT 'C' USER_SEQ, '220' SCORE2 FROM DUAL

) Z

WHERE 1=1

AND X.USER_SEQ = Y.USER_SEQ(+)

AND X.USER_SEQ = Z.USER_SEQ(+)

ORDER BY X.USER_SEQ

;