ORA-01407 with UPDATE using COALESCE function

Question

Hi
We're trying to run the following query as part of an upgrade:
UPDATE LAWSON.NATBALANCE
SET STATEMENT_REQ=(SELECT COALESCE(acm.STATEMENT_REQ,' ')
FROM LAWSON.ARCUSTOMER acm
WHERE acm.NAT_FLAG='N'
AND LAWSON.NATBALANCE.NAT_COMPANY=acm.COMPANY AND
LAWSON.NATBALANCE.NAT_CUSTOMER=acm.CUSTOMER)
But we're getting the following error:
ORA-01407: cannot update ("LAWSON"."NATBALANCE"."STATEMENT_REQ") to null.
I’m confused by this for a couple of reasons. First, the STATEMENT_REQ field in LAWSON.ARCUSTOMER contains no NULLS, and second I thought the whole purpose of the COALESCE function was to return the first non-null result. What am I missing here?
Edited by: ltzwoman on Dec 4, 2012 10:48 AM

Answer 1

Hi,
Welcome to the forum!
Instead of UPDATE, you might prefer to do this with MERGE:
MERGE INTO  lawson.netbalance     dst
USING   (
         SELECT  company
         ,         customer
         ,         COALESCE ( statement_req
                    ) AS statement_req_not_null
         FROM    lawson.arcustomer
     )               src
ON     (   src.company          = dst.nat_company
     AND src.customer     = dst.customer
WHEN MATCHED THEN UPDATE
SET     dst.statement_req     = src.statement_req_not_null
WHERE     dst.statement_req      != src.statement_req_not_null
;You may find this easier to debug and maintain, since in an UPDATE statement, such as the one suggested by Solomon, the sub-query in the SET clause has to be repeated in the WHERE clause.
I hope this answers your question.
If not, post a little sample data (CREATE TABLE and INSERT statements, relevant columns only) for all tables involved, and also post the results you want from that data.
If you're asking about a DML statement, such as UPDATE, the sample data will be the contents of the table(s) before the DML, and the results will be state of the changed table(s) when everything is finished.
Explain, using specific examples, how you get those results from that data.
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