ORACLE 10G group by sorting Suggestion rqd

Question

Hai friends,
recently we migrated from Oracle 9i to oracle 10g. We are instructed that Group by will not sort the records in Oracle 10g, so we are asked to add Order By Clause in wherever applicable in the package.
But after migration i inserted 100 records in 10g database and tested. I am getting correct sorting of records based on Group by column. Can any one explain me why it is? I heard the news sorting will difer on Oracle 10g versions. I am using Oracle Database 10g Enterprise Edition Release 10.2.0.4.0. if it automaticallly sorts, then no need to change the package for sortiing right?
Give me your valuable suggestions..
S

Answer 1

And here's a simple example on 10.2.0.4 that clearly shows the results are not sorted.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP, Data Mining
and Real Application Testing options
SQL> select object_type, count(*) from all_objects group by object_type;
OBJECT_TYPE                     COUNT(*)
CONSUMER GROUP                         2
INDEX PARTITION                      718
TABLE SUBPARTITION                    14
SEQUENCE                             228
SCHEDULE                               1
TABLE PARTITION                      301
PROCEDURE                             21
...Like everyone else has already said, Oracle does not guarantee the order from a group by clause with no order by.
If you need the results in order you must use an order by clause.
Pretty simple really.