请问一下,根据rownum来更新某一字段值这个怎么实现?
Table1
ID     Name   Ordering
1       xx       5
2       yy       6

我想根据Ordering的升序取得rownum来更新ordering
更新之后

ID     Name   Ordering
1       xx       1
2       yy       2

请教高手,这个Sql怎么写啊?
非常感谢,在线等...



------解决方案--------------------
update table1 t1 set ordering=
(select num from
(select t.*,rownum num from table1 t) t2 where t2.id=t1.id)
------解决方案--------------------
CREATE TABLE Table1(ID INTEGER,Name VARCHAR2(10),Ordering INTEGER);
INSERT INTO TABLE1 VALUES(1, 'xx ',5);
INSERT INTO TABLE1 VALUES(2, 'yy ',6);
INSERT INTO TABLE1 VALUES(3, 'yy ',3);
INSERT INTO TABLE1 VALUES(4, 'yy ',7);
INSERT INTO TABLE1 VALUES(5, 'yy ',1);
COMMIT;
SQL> select * from table1 order by Ordering;

ID NAME ORDERING
---------- ---------- ----------
5 yy 1
3 yy 3
1 xx 5
2 yy 6
4 yy 7

SQL> UPDATE TABLE1 T1 SET Ordering=
2 (SELECT RN FROM
3 (SELECT ROWNUM RN,T.* FROM (SELECT * FROM TABLE1 ORDER BY Ordering)T)T2
4 WHERE T1.ID=T2.ID);

已更新5行。

SQL> select * from TABLE1;

ID NAME ORDERING
---------- ---------- ----------
1 xx 3
2 yy 4
3 yy 2
4 yy 5
5 yy 1

SQL> select * from table1 order by Ordering;

ID NAME ORDERING
---------- ---------- ----------
5 yy 1
3 yy 2
1 xx 3
2 yy 4
4 yy 5

不是这个意思吗？