複数フィールドの組み合わせによるユニークな値ごとに最大値を取得する方法

/******  YYYYMMDD(NUM), CHITEN(TXT)フィールドに付きNICHIJI(TXT)フィールドの最大値を取得  ******/

//共通
SELECT * FROM TABLE1
WHERE TABLE1.NICHIJI2 =
(SELECT MAX(TMP.NICHIJI2)
FROM TABLE1 TMP
WHERE TMP.YYYYMMDD=TABLE1.YYYYMMDD
AND TMP.CHITEN=TABLE1.CHITEN)

//SQL Server
SELECT * FROM GeoDatabase.dbo.TABLE1 WHERE
 STR(YYYYMMDD)+CHITEN+NICHIJI2
 IN (SELECT STR(YYYYMMDD)+CHITEN+MAX(NICHIJI2)
 FROM GeoDatabase.dbo.TABLE1
  GROUP BY YYYYMMDD,CHITEN)

//Oracle
SELECT * FROM TABLE1 WHERE 
TO_CHAR(YYYYMMDD)||CHITEN||NICHIJI IN (SELECT TO_CHAR(YYYYMMDD)||CHITEN||MAX(NICHIJI)  FROM TABLE1 GROUP BY YYYYMMDD,CHITEN)