[오라클]특정 열 중복값 null 처리
데이터 생성 with t (col1, col2, col3) AS ( SELECT '아파트1', 60, 30000 FROM DUAL UNION ALL SELECT '아파트1', 60, 35000 FROM DUAL UNION ALL SELECT '아파트1', 70, 40000 FROM DUAL UNION ALL SELECT '아파트1', 80, 45000 FROM DUAL UNION ALL SELECT '아파트2', 100, 50000 FROM DUAL UNION ALL SELECT '아파트2', 120, 50000 FROM DUAL UNION ALL SELECT '아파트3', 100, 50000 FROM DUAL UNION ALL SELECT '아파트4', 100, 50000 FROM DUAL) 방법1 :..