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Home -> Community -> Mailing Lists -> Oracle-L -> RE: sort aggregate vs sort order by
Hi Larry
THX Jack
"Larry Elkins" <elkinsl_at_flash.net>@fatcity.com on 28-12-2001 14:25:18
Please respond to ORACLE-L_at_fatcity.com
Sent by: root_at_fatcity.com
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> cc: (bcc: Jack van Zanen/nlzanen1/External/MEY/NL)
Jack,
I assume you are asking this question in reference to the access path, or explain plan, for a query.
Sort (Aggregate) -- Query returns a single row using a summary function but
does not include a GROUP BY clause.
Sort (Order By) -- Query includes an ORDER BY clause.
Sort (Group By) -- Query includes a GROUP BY clause.
In the 8i documentation, this info can be found in Table 5-4 in the
"Designing and Tuning for Performance" manual. FWIW, though mentioned
elsewhere in the same manual, Table 5-4 doesn't mention the SORT (GROUP BY
NO SORT) -- ordered data is being fed into the GROUP BY step negating the
need for the sort operation that is needed for a GROUP BY. Can occur under
certain conditions -- sometimes when index access supporting the ordering
is
used, after a sort merge, etc.
I attached some examples to illustrate.
Regards,
Larry G. Elkins
elkinsl_at_flash.net
214.954.1781
> -----Original Message-----
> From: root_at_fatcity.com [mailto:root_at_fatcity.com]On Behalf Of
> nlzanen1_at_EY.NL
> Sent: Friday, December 28, 2001 5:00 AM
> To: Multiple recipients of list ORACLE-L
> Subject: sort aggregate vs sort order by
>
>
>
>
> Hi All,
>
>
> I have tried the Oracle Doc's but can't find the answer to what is the
> difference between the two
>
> Anybody can explain??
>
>
> TIA
>
>
>
> Jack
>
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> INET: nlzanen1_at_EY.NL
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(See attached file: examples.txt)
examples.txt
Description: Binary data
Received on Mon Dec 31 2001 - 02:29:57 CST
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