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 |