DB2 FOR LUW / DB2FORLUW / A50 - DB2

A query might return incorrect query result when it has all the 
following characteristics: 
- The query has a UNION ALL query block, e.g. (select * from 
table1 UNION ALL select * from table2), called uaSubQ. 
- The query has LEFT OUTER JOIN query block, whose row 
preserving side includes base table(s) and null producing side 
is uaSubQ, e.g.  (select ... from table3 LEFT OUTER JOIN uaSubQ 
on ... where <predUaT3>) , called lojSubQ. 
- <predUaT3> is a comparison predicate, which references 
column(s) from both uaSubQ and table3. The predicate expression 
consists of CASE expression that has WHEN clause predicate, 
which tests if the null producing side column is null, e.g. 
"WHEN uaSubQ.column IS NULL". 
 
To find whether a query hits this problem, you can generate 
db2exfmt plan and search if "ROWNUMBER" OnLine Analytical 
Processing (OLAP) function is present in the optimized statement 
section.

**************************************************************** 
* USERS AFFECTED:                                              * 
* All users                                                    * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 10.5 and Fix Pack 7                   * 
****************************************************************

Compile query at optimization level 0 or 1.

Problem was first fixed in DB2 Version 10.5 and Fix Pack 7

not known / see Local fix

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

11.06.2015
20.01.2016
11.07.2016