求sql语句。如何随即选择n条数据? 从表table_a中随机选择出n条数据。sql语句怎么写?在线等待!谢谢! 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 再加个条件:where conditions1; select * from (select ...,rownum rn from (select * from twhere ...order by dbms_random.value))where rn<=n; 学习!~ 随机函数:dbms_random.valueORACLE ERP开发基础之Oracle数据库基础 不用想,不用刻意去取随机的数。直接SELECT出来的数即使是有规律的,但是对于你来说也是随机的,直接取前几条就OK了。 select * from ( select tt.* ,rownum rn from ( select * from table_a t order by dbms_random.value) tt) where rn <=n; //n1和n2给个范围,随便找几行数据就可以了,和随机的效果也没有太大的区别,在数据库查询中条件过于复杂会影响系统的性能,尤其对系统配置不是很高的情况下,有时是灾难性的。select * from table_a where rownum>n1 and rownum<n2 顶一下2楼的写法!Select * From (Select col1,col2... From Students s Where conditions1 Order By Dbms_Random.Value) Where Rownum < = N; SELECT * FROM TABLE_A T WHERE ROWNUM < ABS(MOD(DBMS_RANDOM.RANDOM, 100)) Select * From (Select col1,col2... From Students s Where conditions1 Order By Dbms_Random.Value) Where Rownum >N;可以不啊 提高dbms_job.submit的执行效率(跪求高手指教) 存储过程中游标报错 有见行转列 简单问题求助:报错:“ORA-06502: PL/SQL: 数字或值错误 : 字符串缓冲区太小” 请教oracle9i命令行中如何显示一个表的DDL 行级触发器的问题 怎么修改internal用户的密码 急急急!有高手帮我解决吗?1000相送!! 『新手』请问ORACLE8i有没有这样的功能 oracle命令窗口@的sql语句如何获取输入值。。 ORA-27102: out of memory 解决实例 oracle字符串截取查询
select ...,rownum rn
from (
select * from t
where ...
order by dbms_random.value))
where rn<=n;
select tt.* ,rownum rn
from (
select * from table_a t
order by dbms_random.value) tt)
where rn <=n;
select * from table_a where rownum>n1 and rownum<n2
Select *
From (Select col1,col2... From Students s Where conditions1 Order By Dbms_Random.Value)
Where Rownum < = N;
From (Select col1,col2... From Students s Where conditions1 Order By Dbms_Random.Value)
Where Rownum >N;
可以不啊