That's correct, there's no rownum of 0.
ex.
SQL> select rownum, username from dba_users;
ROWNUM USERNAME
---------- ------------------------------
1 SYS
2 SYSTEM
3 OUTLN
4 OEM_DLAND
5 DBSNMP
6 HR
7 PM
8 DLANDRUM
9 OE
10 WMSYS
11 ORDSYS
12 ORDPLUGINS
13 MDSYS
14 CTXSYS
15 QS_CS
16 QS_CB
17 QS_CBADM
18 QS_OS
19 QS_ES
20 QS_WS
21 QS
22 QS_ADM
23 SH
24 XDB
25 ANONYMOUS
26 WKSYS
27 WKPROXY
28 ODM
29 ODM_MTR
30 OLAPSYS
30 rows selected.
I'm not sure what you mean by 'judge the select return', but the only real use I can
think of for rownum is to restrict your query to a small random sampling of your
data...
ex.
SQL> select table_name, tablespace_name from dba_tables
2 where rownum < 5;
TABLE_NAME TABLESPACE_NAME
------------------------------ ------------------------------
SEG$ SYSTEM
CLU$ SYSTEM
OBJ$ SYSTEM
FILE$ SYSTEM
>>> [EMAIL PROTECTED] 03/19/03 08:33AM >>>
Darrell Landrum,-? +��
thanx for your explaination.
I wonder :whether i can judge the select return.
I find the rowNUM is not 0, is right?
======= 2003-03-19 05:03:00 -?+++ -++-- +� =======
>Santosh,
>
>Good question. Actually these 2 are not related.
>Rowid is an actual attribute assigned to each row of a table and is unique.
>Rownum is logically assigned to rows returned in a query (nothing to do with the
>table). It is assigned sequentially as rows are returned (meaning if you can't have
>a rownum 2 until you've gotten a rownum 1).
>
>Ex.
>SQL> select rowid from dual;
>
>ROWID
>------------------
>AAAACsAABAAAAGkAAA
>
>SQL> select rownum from dual;
>
> ROWNUM
>----------
> 1
>
>SQL> select rownum from dual where rownum=2;
>
>no rows selected
>
>SQL> select rownum from dual where rownum < 2;
>
> ROWNUM
>----------
> 1
>
>
>Hope this was helpful,
>Darrell
>
>
>
>
>>>> [EMAIL PROTECTED] 03/19/03 03:43AM >>>
>Hello list,
>
> I wanted to know the concept of Rownum.. Is it similar to Row Id ?
>
>Thanks and Regards,
>Santosh
>
>
>----------------------------------------------------------------------------
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