DB2 FOR LUW / DB2FORLUW / A50 - DB2

WRONG RESULTS ARE POSSIBLE FOR FEDERATED OR COLUMNAR QUERY WITH
AGGREGATION OVER DISTINCT OUTER JOIN
The following query yields wrong results if the source tables
are either federated nicknames or column-organized tables.

with v(a, b) as
 (select distinct t1.c2, t2.c1 from t1 left join t2 on
t1.c1=t2.c2)
select sum(b) as sumofb, a from v group by a
;

e.g. say t1 contains rows (1, 1), (1, 2) and t2 contains rows
(1, 1), (2, 1), (2, 1)

If t1 and t2 are nicknames or if t1 and t2 are column-organized
tables this incorrectly returns:
SUMOFB      A
----------- -----------
          5           2
          5           1

  2 record(s) selected.

But the correct result is this:
SUMOFB      A
----------- -----------
          3           1
          3           2

  2 record(s) selected.

This problem is specific to Outer Join.

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* USERS AFFECTED:                                              *
* ALL                                                          *
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* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
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* RECOMMENDATION:                                              *
* Upgrade to Db2 10.5 Fix Pack 11 or higher                    *
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N/A

not known / see Local fix

forerunner  : IT30249 
follow-up : 

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

11.09.2019
25.02.2020
25.02.2020