Oracle 刪除重複資料

DELETE
FROM TABLE_NAME
WHERE ROWID = ANY(
SELECT ROW_ID
FROM (COLUMN_A, COLUMN_B ,COUNT(*), MAX(ROWID) AS ROW_ID
FROM TABLE_NAME
GROUP BY COLUMN_A, COLUMN_B
HAVING COUNT(*) > 1
)
)

重複執行數次即可，
另一種寫法執行一次，不過比較複雜一點。