DB2 FOR LUW / DB2FORLUW / 970 - DB2

Queries containing UNION or UNION ALL operators with "LIMIT # 
OFFSET #" clause does not behave the same way as FETCH FIRST N 
ROWS ONLY. As such, under these conditions, it may return more 
rows than expected. 
 
Consider a query using the "FETCH FIRST 1 ROW ONLY" clause : 
> select 1 C1 from sysibm.sysdummy1 
  union all 
   select 2 C1 from sysibm.sysdummy1 
   ORDER BY C1 ASC 
   FETCH FIRST 1 ROWS ONLY 
 
Which returns: 
C1 
 
          1 
 
  1 record(s) selected. 
 
 
Using the same data with a "LIMIT 1 OFFSET 0" clause to mimic 
the "FETCH FIRST 1 ROWS ONLY" 
> select 1 C1 from sysibm.sysdummy1 
   union all 
   select 2 C1 from sysibm.sysdummy1 
   ORDER BY C1 ASC 
   LIMIT 1 OFFSET 0 
 
We get more rows than expected if this is used in conjunction 
with UNION or UNION ALL: 
 
C1 
 
          1 
          2 
 
  2 record(s) selected. 
 
> select 1 C1 from sysibm.sysdummy1 
   union all 
   select 2 C1 from sysibm.sysdummy1 
   ORDER BY C1 ASC 
   LIMIT 1 OFFSET 1 
 
C1 
 
          1 
          2 
 
  2 record(s) selected. 
 
 
The problem can be circumvented as follows : 
 
> select * from 
     ( select 1 C1 from sysibm.sysdummy1 
       union all 
       select 2 C1 from sysibm.sysdummy1 
       ORDER BY C1 ASC ) 
    LIMIT 1 OFFSET 0 
 
C1 
 
          1 
 
  1 record(s) selected.

**************************************************************** 
* USERS AFFECTED:                                              * 
* all                                                          * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to version 9.7 Fix Pack 11                           * 
****************************************************************

first fixed in version 9.7 Fix Pack 11

keiner bekannt / siehe Local-Fix

Datum - Problem gemeldet    :
Datum - Problem geschlossen :
Datum - der letzten Änderung:

18.09.2014
08.10.2015
08.10.2015

9.7.FP11