DB2 FOR LUW / DB2FORLUW / A50 - DB2

A query involving outer joins may have the wrong column result
nullability.  For example, the following result column should
have type 493 (nullable BIGINT) but instead returns type 492
(not nullable BIGINT).


   CREATE TABLE T1 ( C1 BIGINT );
   CREATE TABLE T2 ( C2 BIGINT NOT NULL );
   CREATE TABLE T3 ( C3 BIGINT);

   describe
     SELECT T2.C2
     FROM
       T1
       LEFT JOIN T2 ON 1=1
       LEFT JOIN T3 ON 1=1
     WHERE T2.C2 = T3.C3;

    Column Information

    Number of columns: 1

    SQL type              Type length  Column name
Name length
    --------------------  -----------
------------------------------  -----------
    492   BIGINT                    8  C2
2

This only occurs when the semantics of the query dictate a
nullable result, but - due to predicates - the query cannot
actually produce a NULL result.  For this reason, this issue
will rarely be noticeable.  However, it can be a problem in the
following scenarios:

- import/export: import may produce wrong results when the
export was based on such a query
- CREATE TABLE as query, the resulting table column will have
the wrong nullability

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* USERS AFFECTED:                                              *
* ALL                                                          *
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* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
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* RECOMMENDATION:                                              *
* Upgrade to version 10.5 fix pack 10                          *
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not known / see Local fix

forerunner  : 
follow-up : IT22972 

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

18.08.2017
16.07.2018
16.07.2018