sql语句删除重复数据

在一个数据表中没有设置唯一约束导致添加了重复的数据，要想添加唯一约束，首先要把重复记录删除。sql语句：

DELETE FROM &t

WHERE ROWID IN (

SELECT RID

FROM (

SELECT ROWID AS RID, ROW_NUMBER() OVER(

PARTITION BY a1,a2...

ORDER BY ROWID

) RN

FROM &t)

WHERE RN>1);

&t=表名；a1,a2=判断重复的字段