WITH t AS
(
SELECT 'C515' apseq, 1 apdtlseq, 7 seq, '01' status, '10010' empno, '결재요청3' opin, '20210213' apprdt FROM dual
UNION ALL SELECT 'C515', 3, 7, '03', '10020', '걸재승인3', '20210213' FROM dual
UNION ALL SELECT 'C515', 4, 7, '00', '10030', ''         , ''         FROM dual
UNION ALL SELECT 'C515', 1, 6, '01', '10010', '결재요청3', '20210213' FROM dual
UNION ALL SELECT 'C515', 3, 6, '00', '10020', ''         , ''         FROM dual
UNION ALL SELECT 'C515', 4, 6, '00', '10030', ''         , ''         FROM dual
UNION ALL SELECT 'C515', 1, 5, '01', '10010', '결재요청2', '20210211' FROM dual
UNION ALL SELECT 'C515', 3, 5, '09', '10020', '결재반려2', '20210211' FROM dual
UNION ALL SELECT 'C515', 4, 5, '00', '10030', ''         , ''         FROM dual
UNION ALL SELECT 'C515', 1, 4, '01', '10010', '결재요청2', '20210211' FROM dual
UNION ALL SELECT 'C515', 3, 4, '00', '10020', ''         , ''         FROM dual
UNION ALL SELECT 'C515', 4, 4, '00', '10030', ''         , ''         FROM dual
UNION ALL SELECT 'C515', 1, 3, '01', '10010', '결재요청1', '20210210' FROM dual
UNION ALL SELECT 'C515', 3, 3, '03', '10020', '결재승인1', '20210210' FROM dual
UNION ALL SELECT 'C515', 4, 3, '09', '10030', '결재반려1', '20210210' FROM dual
UNION ALL SELECT 'C515', 1, 2, '01', '10010', '결재요청1', '20210210' FROM dual
UNION ALL SELECT 'C515', 3, 2, '03', '10020', '결재승인1', '20210210' FROM dual
UNION ALL SELECT 'C515', 4, 2, '00', '10030', ''         , ''         FROM dual
UNION ALL SELECT 'C515', 1, 1, '01', '10010', '결재요청1', '20210210' FROM dual
UNION ALL SELECT 'C515', 3, 1, '00', '10020', ''         , ''         FROM dual
UNION ALL SELECT 'C515', 4, 1, '00', '10030', ''         , ''         FROM dual
)
SELECT a.*
  FROM t a
     , (SELECT apseq, opin
             , MAX(seq) seq
          FROM t
         WHERE apdtlseq = 1
         GROUP BY apseq, opin
        ) b
 WHERE a.apseq = b.apseq
   AND a.seq   = b.seq
;