DB2 FOR LUW / DB2FORLUW / A50 - DB2

DB2 may incorrectly return SQL0420N while compiling a query
containing one or more UNION ALL operators.

The UNION ALL operator(s) can either be as part of the main
query or within subqueries.

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* USERS AFFECTED:                                              *
* ALL                                                          *
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* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
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* RECOMMENDATION:                                              *
* See Local Fix                                                *
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1. Rewrite the query to avoid using UNION ALL operators.

Or:

2. Set the current registry variable via db2set:

db2set -im DB2COMPOPT=NO_DEEPKEYPU

Or for specific queries by using the following REGISTRY
optimizer guideline:

not known / see Local fix

forerunner  : 
follow-up : IT22505 

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

19.09.2017
12.07.2018
12.07.2018