--
从一个表中随机取两条记录
--
1.dbms_random.value
select
*
from
(
select
*
from
t_ums_config
order
by
dbms_random.value)
where
rownum
<=
2
;
--
2.dbms_random.random
select
*
from
(
select
*
from
t_ums_config
order
by
dbms_random.random)
where
rownum
<=
2
;
--
3.sys_guid()
select
*
from
(
select
*
from
t_ums_config
order
by
sys_guid())
where
rownum
<=
2
;
--
4.sample(20) 按百分比
select
*
from
(
select
*
from
t_ums_config sample(
20
))
where
rownum
<=
2
;
--
5.sample block(20) 按数据块
select
*
from
(
select
*
from
t_ums_config sample block(
40
))
where
rownum
<=
2
;
