WITH test AS
(
SELECT '김유신' nam FROM dual
UNION ALL SELECT '강감찬' FROM dual
UNION ALL SELECT '이명벅' FROM dual
UNION ALL SELECT '뇌물현' FROM dual
UNION ALL SELECT '이순신' FROM dual
UNION ALL SELECT '이순신' FROM dual
UNION ALL SELECT '김구' FROM dual
UNION ALL SELECT '토마스' FROM dual
UNION ALL SELECT '토마스' FROM dual
)
SELECT Decode(rn2,1,rn,NULL) seq,
nam
FROM
(SELECT nam , rn ,
Row_Number() over(PARTITION BY nam,rn ORDER BY nam) rn2
FROM
(SELECT nam,
dense_Rank() over(ORDER BY nam) rn
FROM test)
)

감사합니다. oracle 버젼이 8.0인데요 ~!분석 함수가 안되네요~!
서성우님 감사합니다.

WITH T AS(
SELECT '김유신' AS A FROM DUAL UNION ALL
SELECT '김강찬' AS A FROM DUAL UNION ALL
SELECT '이명벅' AS A FROM DUAL UNION ALL
SELECT '뇌물현' AS A FROM DUAL UNION ALL
SELECT '이순신' AS A FROM DUAL UNION ALL
SELECT '이순신' AS A FROM DUAL UNION ALL
SELECT '김구' AS A FROM DUAL UNION ALL
SELECT '토마스' AS A FROM DUAL UNION ALL
SELECT '토마스' AS A FROM DUAL
)
SELECT
DECODE(LAG(A) OVER(ORDER BY NO),A,'',NO) AS RN
, A
FROM
(
SELECT
ROWNUM NO
, A
FROM T
)

-- 순위부여 규칙이 모호하네요
-- 이름컬럼만으로는 위와 같은 순서가 안나옵니다.
-- 아래쿼리는 이름순으로 정렬했습니다. 원하시는 결과물과는 순서가 다릅니다.
SELECT t1.name, COUNT(DISTINCT t2.name) + 1 rk
FROM (SELECT ROWNUM rn, name FROM test) t1, test t2
WHERE t1.name > t2.name(+)
GROUP BY t1.name, t1.rn
;