| Hlp in Qry [message #8668] |
Wed, 17 September 2003 23:42  |
Cindreen Clarence
Messages: 41
Registered: March 2003
Location: Bangalore
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Member |
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Hi All,
Could any1 pls tell me 'How 2 retrieve every 3rd record of a table'?
thank u.
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| Re: Hlp in Qry [message #8675 is a reply to message #8668] |
Thu, 18 September 2003 04:22  |
R.Satish Kumar
Messages: 14
Registered: August 2003
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Junior Member |
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Hi,
select * from
(select empno,rownum rm from emp) a
where mod(a.rm,3) = 0;
Hope this will solve your query..
Regards,
Satish.R
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| Re: Hlp in Qry [message #8677 is a reply to message #8668] |
Thu, 18 September 2003 05:20 |
Ani
Messages: 56
Registered: November 2000
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Member |
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select * from table_name
where rowid in
(select rid from
(select rowid rid, rownum rn from table_name)
where mod(rn,3) = 0)
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| Re: Hlp in Qry [message #8683 is a reply to message #8668] |
Thu, 18 September 2003 07:54 |
Thiru
Messages: 1089
Registered: May 2002
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Senior Member |
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Cini,
How do you define '3rd record of a table' ?
Oracle may not return results in any predictable order ,unless you (explicit or implicit) order them by specific column(s)
Rowid tells you the physical location of a record in terms of File#,Block#,Record# and MAY BE REUSED and CHANGED internally, hence providing no guarantee.
Rownum assigns row numbers as they are returned in a result set. You cannot get ROWNUM=3;
You will have to specify the criteria for ordering rows in your result set.
Hope this helps
Thiru
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| I totaly agree with Thiru [message #8695 is a reply to message #8683] |
Fri, 19 September 2003 03:17 |
Mike
Messages: 417
Registered: September 1998
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Senior Member |
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I totaly agree with Thiru.
The 2 other given solution may seem to work but in fact they are not correct for the reason given by Thiru.
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