Why is this flawed query working fine? -Answered

Question

DB Version:10gR2
I wanted to reproduce the flaw of using rownum when used with an ORDER BY clause.
Because ORDER BY is evaluated at last (after ROWNUMs are generated), the below query should give wrong result set most of the time.
But the following query
select ename,join_date
from test
where rownum<4
order by join_dateis giving me the correct result. So , when will this query start giving wrong results?
alter session set nls_date_format='DD-MM-YYYY HH:MI:SS';
SELECT SYSDATE FROM DUAL;
SYSDATE
15-12-2008 11:40:30
create table test
(ename varchar2(15),
join_date date);
insert into test values('JAMES',SYSDATE);
insert into test values('CHESTER',SYSDATE);
insert into test values('SUNITA',SYSDATE);
insert into test values('GARRY',SYSDATE);
insert into test values('KAREN',SYSDATE);
insert into test values('ABDUL',SYSDATE);
insert into test values('YING',SYSDATE);
set lines 400
select * from test;
ENAME           JOIN_DATE
JAMES           15-12-2008 11:41:21
CHESTER         15-12-2008 11:41:40
SUNITA          15-12-2008 11:41:56
GARRY           15-12-2008 11:42:17
TIM             15-12-2008 11:42:44
KAREN           15-12-2008 11:52:46
ABDUL           15-12-2008 11:53:01
YING            15-12-2008 11:53:18
CHAICE          15-12-2008 12:14:27
THELMA          15-12-2008 12:14:54
select ename,join_date
from test
where rownum<4
order by join_date;
ENAME           JOIN_DATE
JAMES           15-12-2008 11:41:21   --correct
CHESTER         15-12-2008 11:41:40   --correct     
SUNITA          15-12-2008 11:41:56   --correctEdited by: Nichols on Dec 15, 2008 3:37 AM
Edited by: Nichols on Dec 15, 2008 3:56 AM
Edited by: Nichols on Dec 15, 2008 4:09 AM

Answer 1

Nichols wrote:
I am an Indian . With Indian login names my questions were ignored a lot of times especially in 'Database-General'?
Who knows, we might have OTN members who are racists, Ultra-nationalists, people frustrated with outsourcing,...etc.
I had felt that 'Database-General' ace SYBRAND was one such user.But he is fine now.
When whiteman runs out money i don't know what he can become. No one knows coz they were never poor in the last 50 years.
I for one am so used to poverty.
Edited by: Nichols on Dec 15, 2008 4:28 AMComplete nonsense, imho. This is still mainly a technical forum. My impression is that the only thing that influences the quality of the forum answers is the quality of the initial question. In this thread your question was good. it had almost all the necessary information and it was ask in a precise and orderly manner.
I myself answer nice questions in a nice way and rude questions ("very urgent!!!!") in a rude way. I know better, but sometimes I can't resist. Maybe check some of your older question, and think if you would have asked them differently with the knowledge you have now.
Of cause there are intra cultural differences, especially in the way how people speak and write. Some nations/cultures are more direct in their answers (e.g. germans), while others feel a need for an extra portion of politeness (e.g. indians). It is a good thing to be aware of such differences and not to misinterprete this as raceism or other silly stuff.