Oracle Cannot Update TOP N Issue, 请专家解答

大家好

上周写了匿名方法一文，很多读者，很高兴，相信我们已经从大伙的回复中，对.NET又有了更深刻的认识.

好，现在说主题，各类数据库都有相应更新本表top n的方案.现在我一一举例

首先看表结构如下：

数据库以及表创建命令初始化数据库语句

 CREATE TABLE student(
 id varchar(256)   NOT NULL,
 name varchar(256)   NULL,
 age int NULL)

 insert into student values('','wfg',20);
 insert into student values('','lxx',21);
 insert into student values('','wly',3);
 insert into student values('','jcj',60);
 insert into student values('','wss',60);
 insert into student values('','xsm',60);
 insert into student values('','lcf',60);
 insert into student values('','wjy',35);
 insert into student values('','hyf',35);
 insert into student values('','lwl',12);

表格结构如下：

ID	Name	Age
001	wfg	20
002	lxx	21
003	wly	3
004	jcj	60
005	wss	60
006	xsm	60
007	lcf	60
008	wjy	35
009	hyf	35
010	hwl	12

需求如下：按姓名顺序后，更新前５个的年龄为100岁，如何办到.

首先说下MSSQL

 --方案1失败
 update top(5) student set age = 100  order by name;
 --方案2ok
 update  student set age = 100 where id in (select top 5 id from student order by name );
 select top(5) * from student order by name;

很成功，干得漂亮！

接下来我们看看MYSQL呢，拭目以待...

 update student set age = 100  order by name limit 5;
 select * from student order by name limit 5;

Good news, MySql干得不错，

接下来我们再看看oracle呢？

 --方式１失败
 update student set age = 100 where  rownum <5 order by name ;
 commit;
 --方式２失败
 update student set age = 100 where id in (select id from student  where rownum<5 order by name);
 commit;
 select * from student where rownum<5 order by name;

目前为此，还没有在oracle里找到办法，请数据库专家指导，感谢为盼！