SQL Join then combine columns from the result - sql

Question

So I have two db2 tables. One contains work order information like id, requester name, user, description, etc. Second table that has notes, which is keyed to the id of the other table. The notes field is a 255 text field (Yeah don't suggest changing it, I have no control over it). So there could be multiple results, or none, in the note field depending on obviously how many notes there are.
I have a query which fetches the results. The problem is that I am getting multiple results form the join because there are multiple entries.
So my question is how do I concat/merge the results from the notes table into one field for every result? Thanks
Code:
SELECT
p.ABAANB AS WO_NUMBER,
p.ABAJTX AS Description,
i.AIAKTX as Notes
FROM
htedta.WFABCPP p LEFT JOIN HTEDTA.WFAICPP i
ON i.AIAANB = p.ABAANB
WHERE
p.ABABCD = 'ISST' AND p.ABAFD8 = 0

Answer 1

Have you tried LISTAGG
https://www.ibm.com/developerworks/mydeveloperworks/blogs/SQLTips4DB2LUW/entry/listagg?lang=en
It will allow you to merge all those pesky fields that are causing the additional records... Something like this...
SELECT p.ABAANB AS WO_NUMBER, p.ABAJTX AS Description, LISTAGG(i.AIAKTX, ' ') as Notes
FROM htedta.WFABCPP p
LEFT JOIN HTEDTA.WFAICPP i
ON i.AIAANB = p.ABAANB
WHERE p.ABABCD = 'ISST'
AND p.ABAFD8 = 0
GROUP BY p.ABAAMB, p.ABAJTX

Answer 2

What version of DB2 are you on? If you're using DB2 Linux/Unix/Windows (LUW), then this should work for you:
SELECT p.ABAANB AS WO_NUMBER,
p.ABAJTX AS Description,
,SUBSTR(
xmlserialize(
xmlagg(
xmltext(
concat(',' , TRIM(i.AIAKTX))
)
) AS VARCHAR(4000)
)
,2) AS NOTES
FROM htedta.WFABCPP p
LEFT JOIN HTEDTA.WFAICPP i
ON i.AIAANB = p.ABAANB
WHERE p.ABABCD = 'ISST'
AND p.ABAFD8 = 0
GROUP BY p.ABAANB,
p.ABAJTX

Answer 3

If you are running DB2 at least 9.7, you should be able to use the XMLAGG function similar to this
WITH CombinedNotes( aiaanb, aiaktx) AS (
SELECT aiaanb
, REPLACE( REPLACE(
CAST( XML2CLOB(
XMLAGG( XMLELEMENT(
NAME 'A'
, aiaktx
))
) AS VARCHAR( 3000))
, '<A>',''), '</A>', '')
FROM Htedta.WfaIcpp)
SELECT p.ABAANB AS WO_NUMBER, p.ABAJTX AS Description, i.AIAKTX as Notes
FROM htedta.WFABCPP p
LEFT JOIN CombinedNotes i
ON i.AIAANB = p.ABAANB
WHERE p.ababcd = 'ISST'
AND p.abafd8 = 0;
If you have an earlier version of DB2, or your login for some reason does not permit the XML functions, you can solve the problem with a recursive query. Both techniques are described in the following blog
http://ibmmainframes.com/about44805.html