RE: Why this SQL does not work?

From: Kevin Lange <kgel_at_ppoone.com>
Date: Wed, 11 Jul 2001 16:26:58 -0700
Message-ID: <F001.003481D1.20010711154521@fatcity.com>

Doh .... as the man would say.

Absolutely, how can you have a rownum > or directly equal to a number other than 1 when by the very nature that can never happen.

If you say = 5 or > , it will never happen without the rest of the data there to increment the rownum to 5.

-----Original Message-----
Sent: Wednesday, July 11, 2001 5:13 PM
To: Multiple recipients of list ORACLE-L

Rao,

This snippet from The Fine Manual explains it all... "= 5" or "> 1" will return 0 rows:

Conditions testing for ROWNUM values greater than a positive integer are always false. For example, this query returns no rows:

SELECT * FROM emp

WHERE ROWNUM > 1; The first row fetched is assigned a ROWNUM of 1 and makes the condition false. The second row to be fetched is now the first row and is also assigned a ROWNUM of 1 and makes the condition false. All rows subsequently fail to satisfy the condition, so no rows are returned.

Jack

Jack C. Applewhite
Database Administrator/Developer
OCP Oracle8 DBA
iNetProfit, Inc.
Austin, Texas
www.iNetProfit.com
japplewhite_at_inetprofit.com
(512)327-9068

-----Original Message-----
Maheswara
Sent: Wednesday, July 11, 2001 4:44 PM
To: Multiple recipients of list ORACLE-L

List,

Following are two SQL statements. The first SQL statement works OK (where ROWNUM < 5 is used). The second SQL statement does not return any rows
(where ROWNUM = 5 is used). This table contains 200 records.

First SQL statement

SELECT * FROM
(SELECT PROCESSED_DATE

     FROM TRADES WHERE PROCESSED_STATUS = 0
          ORDER BY ENTRY_DATE)

WHERE ROWNUM < 5

Second SQL statement

SELECT * FROM
(SELECT PROCESSED_DATE

     FROM TRADES WHERE PROCESSED_STATUS = 0
          ORDER BY ENTRY_DATE)

WHERE ROWNUM = 5

Question:

Why second SQL statement does not work?

I would be thankful for the clarification.

Thanks,

Rao
Maheswara.Rao_at_Sungardp3.com

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Received on Wed Jul 11 2001 - 18:26:58 CDT