Oracle删除表中的重复数据

Oracle数据库删除表中的重复数据，以两个字段为例，提供两种方法

①、直接delete重复的数据

delete from table_name t1  where  (t1.col1, t1.col2) in (select col1, col2 from table_name group by col1, col2 having count(*) > 1)  and   t1.rowid not in (select min(rowid) from table_name group by col1, col2 having count(*) > 1) ;

②、查询出所有不重复的数据，入到一张中间表中，然后把原表的数据清空，最后把中间表的数据入到原表中

--数据入到中间表中 insert into table_mid_name  select t1.* from table_name t1  where t1.rowid in (select min(rowid) from table_name group by col1, col2 ) ; --清除原表数据 truncate table table_name ; --数据入到原表中 insert into table_name select * from table_mid_name ;