Re: how to fetch the first n rows only for a query

Yep..But even then its not the 'first' xzy records; just less than xyz rows of a pre-sorted set. The earliest timestamp ( if one was included in the row) could be the first ( or the last ) record depending on what first ( or last) means ( Most recently added or modified, oldest).. It gets almost metaphysical after that....

"Telemachus" <telemachus_at_ulysseswillreturn.net> wrote:

>Yes but as someone else pointed out use an inline query to get what you want
>
>
>select abc from ( select <your query > order by blah ) where rownum < xyz
>
>and yes, I agree, but when would it be important to retrieve this
>information in a relational framework ?
>
>and I would regard the first record as the one with the earliest timestamp
>if there was one and so on...
>"TurkBear" <jgreco1_at_mn.rr.com> wrote in message
>news:l060ku0bbqfg6p9mjorqr4c8kcngd8a2v1_at_4ax.com...
>>
>> One additional nitpick.
>> .The rows returned by a where rownum < 25 ( or whatever)
>> are, by no means, the FIRST 25 records in the database - The concept of
>first or last ( or second or whatever number)
>> is meaningless in a RDBMS - the 'order' in which rows are stored in not
>determinate and may change ( probably will if many
>> changes to the table are made)
>> The rownum < 25 just limits the number or rows returned, nothing else.
>>
>> My 2c on one of my pet peeves....
>>
>>
>> Fan Ruo Xin <fanruox_at_yahoo.com> wrote:
>>
>> >Thank you, Howard!
>> >I did think they are the same thing. Thanks for your correcting me.
>> >BTW, I am jsut curious when ORACLE introduce rownum?
>> >Regards,
>> >FRX
>> >
>> >"Howard J. Rogers" wrote:
>> >
>> >> Don't get too carried away... ROWID is not the same thing as ROWNUM at
>all,
>> >> and ROWID is still bad to use in a relational database, because you
>have no
>> >> control whatsoever over what rows get which rowids. And once assigned a
>> >> rowid, a row always retains that same rowid (with one or two exceptions
>> >> introduced in Oracle 8i). So a test on rowid<x.x.x.x would always
>return
>> >> exactly the same set of rows, regardless of what order by clause you
>put in,
>> >> or what changes you make to the data.
>> >>
>> >> But ROWNUM is assigned once a row has been selected. And that's why the
>> >> 'ROWNUM<x' thing works.
>> >>
>> >> Regards
>> >> HJR
>> >>
>> >> "Fan Ruo Xin" <fanruox_at_yahoo.com> wrote in message
>> >> news:3D3E07EE.72CC7B8D_at_yahoo.com...
>> >> > Thanks for the response from you all!!!
>> >> > I always forget "rowid/rownum". I used to think "rowid" is not a good
>idea
>> >> > when you use SQL for relational DBMS. Now I chang my thinking.
>> >> > Regards,
>> >> >
>> >> >
>> >> > Fan Ruo Xin wrote:
>> >> >
>> >> > > Hi,
>> >> > > I have a very simple query like,
>> >> > > SELECT ...
>> >> > > FROM MyTable
>> >> > > WHERE
>> >> > > ORDER BY
>> >> > >
>> >> > > Both the tablesize of mytable and result size are very big. I only
>care
>> >> > > the first 10 or 20 rows from the result set. How to implement it in
>> >> > > ORACLE?
>> >> > > BTW, I searched SELECT stmt in SQL Reference, got no help.
>> >> > >
>> >> > > Regards,
>> >> > > Fan Ruo Xin
>> >> >
>>
>>
>>
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   http://www.newsfeed.com The #1 Newsgroup Service in the World! -----= Over 100,000 Newsgroups - Unlimited Fast Downloads - 19 Servers =----- Received on Thu Jul 25 2002 - 12:21:26 CDT