在Oracle中如何利用Rowid查找和删除表中的重复记录

在Oracle中如何利用Rowid查找和删除表中的重复记录(3)          5          3   dar
         6          1   wee
         7          2   zxc

20 rows selected.

1.查找重复记录的几种方法：
(1).SQL>select * from cz group by c1,c10,c20 having count(*) >1;
        C1        C10 C20
---------- ---------- ---
         1          2   dsf
         2          3   che
         3          4   dff

(2).SQL>select distinct * from cz;

        C1        C10 C20
---------- ---------- ---
         1          2   dsf
         2          3   che
         3          4   dff

(3).SQL>select * from cz a where rowid=(select max(rowid) from cz where c1=a.c1 and c10=a.c10 and c20=a.c20);
        C1        C10 C20
---------- ---------- ---
         1          2   dsf
         2          3   che