Hello,
The following code will select 5 rows out of a random set of rows from the emp (employee) table
select *
from (
select ename, job
from emp
order by dbms_random.value()
)
where rownum <= 5
my concern is that the inner select will cause a table scan in order to assign a random value to each row. This code when used against a large table can be a performance problem.
Is there an efficient way of selecting random rows from a table without having to do a table scan ? (I am new to Oracle, therefore it is possible that I am missing a very simple way to perform this task.)
thank you for your help,
John.
Edited by: 440bx on Jul 10, 2010 6:18 PM