Oracle删除重复数据的几种方式

包含空字段的数据去重：

DELETE FROM TABLE_NAME WHERE ROWID NOT IN
(SELECT MIN(ROWID) FROM TABLE_NAME GROUP BY COLUMN1,COLUMN2)

不包含空字段的数据去重：

DELETE FROM TABLE_NAME T
WHERE (T.COLUMN1,T.COLUMN2) IN (
  SELECT COLUMN1,COLUMN2 FROM TABLE_NAME 
  GROUP BY COLUMN1,COLUMN2 HAVING COUNT(1) >1
)
AND ROWID NOT IN(
  SELECT MIN(ROWID) FROM TABLE_NAME 
  GROUP BY COLUMN1,COLUMN2 HAVING COUNT(1)> 1
)

以上两种方式都适用：

写法1：

DELETE FROM TABLE_NAME T WHERE T.ROWID IN(
    SELECT A.ROWID FROM (
	  SELECT ROWID,ROW_NUMBER()OVER(PARTITION BY COLUMN1,COLUMN2 ORDER BY COLUMN1) RN FROM TABLE_NAME
    ) A WHERE A.RN>1
)

写法2：

DELETE FROM TABLE_NAME T2 WHERE NOT EXISTS 
(SELECT 1 FROM (SELECT MIN(ROWID) RID FROM TABLE_NAME GROUP BY COLUMN1,COLUMN2) T1 WHERE T1.RID=T2.ROWID)