oracle删除重复数据方法

删除ORACLE重复的数据常用方式，根据rowid来编写SQL脚本:

 

delete from t_web
 where rowid in (select a.rowid, a.web_name
                   from t_web a, t_web b
                  where a.rowid > b.rowid
                    and a.web_name = b.web_name);
                   
delete from t_web a
 where rowid not in
       (select max(b.rowid) from t_web b  where a.web_name = b.web_name )
      
delete from t_web
where rowid not in (select max(rowid) from t_web a group by a.web_name);                       

 

delete from tbl
 where (col1, col2) in
       (select col1, col2 from tblgroup bycol1, col2havingcount(*) > 1)
   and rowidnotin(selectnin(rowid) fromtblgroup bycol1,
                  col2havingcount(*) > 1);