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DB2 - Problem description

Problem IT01660 Status: Closed

INCORRECT RESULTS MIGHT BE PRODUCED WITH PREDICATES INVOLVING NULL
CONSTANTS

product:
DB2 FOR LUW / DB2FORLUW / 970 - DB2
Problem description:
Under rare scenarios, DB2 might produce an incorrect result if 
the following conditions are true: 
1) The query contains a NULL constant in predicate 
2) The predicate is of the form expression <relop> NULL where 
<relop> can be =,>=,<= 
3) The expression is either a CASE expression or a NULLIF 
function 
4) The output of the expression is guaranteed to be NULL 
 
eg. 
select * from t1 where NULLIF (c1, c1) >= Cast(NULL as int); 
select * from t1 where case when c1 = c1 then NULL else c1 end 
>= cast(NULL as BIGINT);
Problem Summary:
**************************************************************** 
* USERS AFFECTED:                                              * 
* All users                                                    * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 version 9.7.0.10.                             * 
****************************************************************
Local Fix:
1) drop the redundant predicate 
2) Change the query optimization level to 0
Solution
The problem is first fixed in DB2 version 9.7.0.10.
Workaround
not known / see Local fix
Timestamps
Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :
08.05.2014
08.12.2014
21.04.2015
Problem solved at the following versions (IBM BugInfos)
9.7.0.10
Problem solved according to the fixlist(s) of the following version(s)
9.7.0.10 FixList