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Problem IT35943
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Status: Closed |
WRONG RESULT: QUERIES REFERENCING AN EXISTS SUB-QUERY WITH FETCHFIRST 1 ROW REFERENCED IN A CASE STATEMENT IN THE SELECT LIST
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| product: |
DB2 FOR LUW / DB2FORLUW / B50 - DB2 |
| Problem description: |
Queries referencing an EXISTS sub-query with FETCH FIRST 1 ROW
referenced in a CASE statement in the SELECT list may result in
incorrect results.
Steps to reproduce
create table tab2 ( col1 integer );
create table tab3 ( col2 integer );
insert into tab2 values ( 123 );
insert into tab2 values ( 234 );
insert into tab2 values ( 345 );
insert into tab2 values ( NULL );
insert into tab3 values ( 234 );
insert into tab3 values ( 345 );
insert into tab3 values ( NULL );
select a.col1 , case when exists ( select 1 from tab3 b where
a.col1 = b.col2 fetch first 1 rows only ) then 1 else 0 end C
from tab2 a where col1 is not null
Expected output
COL1 C
----------- -----------
123 0
234 1
345 1
With tables organized by column, we get this incorrect result
COL1 C
----------- -----------
123 0
234 1
345 0
1) Remove FETCH FIRST 1 ROW as it is not required in an
existential sub-query
2) In DPF environment, apply the following guideline to the
query:
/*
*/
3) In non-DPF, apply the following guideline:
/*
*/ |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to 11.5.6 *
**************************************************************** |
| Local Fix: |
|
| Solution |
|
| Workaround |
****************************************************************
* USERS AFFECTED: *
* All *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to 11.5.6 *
**************************************************************** |
| Comment |
Upgrade to 11.5.6 |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 17.02.2021
11.06.2021
23.06.2021 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
