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Problem IT01073
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Status: Closed |
INCORRECT RESULTS MIGHT BE PRODUCED WITH PREDICATES INVOLVING NULL CONSTANTS |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - 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 10.1.0.4. *
**************************************************************** |
| Local Fix: |
1) drop the redundant predicate
2) Change the query optimization level to 0 |
| available fix packs: |
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
|
| Solution |
The problem is first fixed in DB2 version 10.1.0.4. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 15.04.2014
08.05.2014
21.04.2015 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.4
|
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