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Working of ROWNUM? [message #65455] Thu, 23 September 2004 05:17 Go to next message
aloksarkar
Messages: 1
Registered: September 2004
Junior Member
When i wirte Like
SELECT *
FROM emp
WHERE ROWNUM=1;
It Will Give Me the Right Data .Even insted of 1 When i Put In Where Condition Like ROWNUM<9,ROWNUM<=1Give me the Right Data.

It Will Not Give Me the Right Data When I write Like
ROWNUM>1
ROWNUM>2
............

What is the Internal Working Of ROWNUM in SQL ...
plz ...Can Any body Help Me ?
Re: Working of ROWNUM? [message #65457 is a reply to message #65455] Thu, 23 September 2004 08:37 Go to previous message
VISHNU
Messages: 14
Registered: November 2001
Junior Member
Oracle's ROWNUM is a sequence number generator. It always starts with 1. The sequence numbers are assigned to each row as they are selected. So when you say "ROWNUM > 1" , you are implicitly asking oracle to assign rownumbers starting from 2, which it cannot do and so you wouldn't get any rows. For testing, try "ROWNUM >=1" where you are asking the rownum to be assigned from 1 and all the rows will get selected.

Summary: Any condition which involves "ROWNUM" should ask Oracle to start assigning rownumbers starting from "1". All other conditions fail.
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