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Never rely on GROUP BY when you need sorted data:
the only way to ensure any sort order is by using ORDER BY. This is true for all Oracle versions. See this post for details:
Tell your developers: garbage in - garbage out. In relational databases only ORDER BY ensures row order. If your developers relied on GROUP BY implemented by SORT and therefore returning ordered rows they had to realize code they wrote is Oracle release dependent and sooner or later code would require changes. And that "sooner or later" is now reality. In newer versions ORACLE can do GROUP BY via SORT or via HASH. And if it is done via HASH - don't expect ordered results. So tell your developers "payback time".
As I understand the question of OP, he understands the problem with sorting and grouping.
somebody could give the list of other difference in behavior (SQL and PL/SQL) agter migrating from 9i to 11g
I do not know any other problems.
Maybe someone knows other problems he can expect?
I guess that for some queries the execution plans will be different on 11g.
This might perhaps lead to bad performance in some cases...
This might be an interesting read for OP: http://www.oracle.com/technetwork/database/focus-areas/manageability/9i-to-11g-real-world-customer-exper-133754.pdf
thanks peter, my question is
Somebody could give me the list of other difference in behavior (SQL and PL/SQL) after migrating from 9i to 11g
the problem sort of "group by " is not very important.
i thanks everybody who could give a document or URL of these differences.
Edited by: hoek on Feb 17, 2012 3:42 PM
is there any other solution more détailled?
thanks for all answers above
Noticing some changes in PL/SQL from 9i to 11g.
Previously compiled code ( 9i ) now refuses to compile ( 11g ) with PLS-00371. Guessing that scope somehow changed?
have u more detalilled answer about this subject
thanks a lot