Thanks Birgitta
Some of this (who am I kidding) - MOST of this is brand new to me - so I will need to look up quite a lot of this to understand (hopefully) what this all means
Any - I changed your query to use the correct file name and field names
Select Min(Connect_By_Root(CMOldCst#)) StartOldCust, CMNewCst#
from prodfa.cstmerge
Where connect_by_isleaf = 1
start with CMOldCst# > 0
connect by Prior CMNewCst# = CMOldCst#
Group By CMNewCst#
Order By StartOldCust
But it failed with
Selection error involving field *N.
When I prompt F1 over this message, it displays
Message ID . . . . . . : QRY2283 Severity . . . . . . . : 30
Message type . . . . . : Information
Message . . . . : Selection error involving field *N.
Cause . . . . . : The query did not run because of a comparison operand
involving data from field *N (in record 281591 of file CSTMERGE in PRODFA if
other than *N). The *N data is not necessarily incorrect, since the operand
could be an expression involving other fields and constants as well as *N,
or it could require some sort of conversion that could not be performed
successfully.
To determine the specific cause of this problem, and to see if additional
problems have been encountered in processing other fields or records, use
the Display Job Log (DSPJOBLOG) command or press F10=Display messages in job
log.
Looking at the job log - the following is displayed
Select or omit error on field SelectRela_1cycleMarkFld_5) member CSTMERGE.
When I F1 prompt on that
Cause . . . . . : A select or omit error occurred in record 281591, record
format *FIRST, member number 1 of file CSTMERGE in library PRODFA, because
of condition 6 of the following conditions:
and condition 6 is
6 - A data mapping error occurred on the field before the select or omit
operation was attempted.
It just so happens that record number 281591 does not exist
The LAST record (in rrn order) is 281590
Alan Shore
E-mail : ASHORE@xxxxxxxx
Phone [O] : (631) 200-5019
Phone [C] : (631) 880-8640
'If you're going through hell, keep going.'
Winston Churchill
-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Birgitta Hauser
Sent: Thursday, May 03, 2018 1:32 AM
To: 'Midrange Systems Technical Discussion' <midrange-l@xxxxxxxxxxxx>
Subject: RE: Recursive SQL queries
Try whether the following SELECT statement will return what you expected (assumed the table has 2 columns called OldCust and NewCust) Create Table qtemp/MyTable (OldCust Integer Not NULL default 0, NewCust Integer Not NULL Default 0);
Select Min(Connect_By_Root(OldCust)) StartOldCust, NewCust from Mytable Where connect_by_isleaf = 1 start with OldCust > 0 connect by Prior NewCust = OldCust Group By NewCust Order By StartOldCust;
Mit freundlichen Grüßen / Best regards
Birgitta Hauser
"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)
"If you think education is expensive, try ignorance." (Derek Bok) "What is worse than training your staff and losing them? Not training them and keeping them!"
"Train people well enough so they can leave, treat them well enough so they don't want to." (Richard Branson)
-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxx> On Behalf Of Alan Shore
Sent: Mittwoch, 2. Mai 2018 15:32
To: midrange-l@xxxxxxxxxxxx
Subject: Recursive SQL queries
Hi everyone
Before I forget - we are on V7r1
Here is my situation
When an order is placed, a customer record is created from the name and address of the person placing that order.
This creates a unique customer number - unless its recognized that this particular customer has already placed an order (How that recognition works is not part of this situation)
However - the person placing the order COULD have already placed an order in the past - but the name and/or address slightly different Todays order was placed by John Smith of a certain address He could have placed a past order as J Smith Or even Johnathan Smith
In these instances, these 3 customer records (and their statistics) need to be merged into one
That is happening, and we keep an audit trail of what old customer number was merged into what "NEW" customer number This data is in a file with 2 fields Old customer number New customer number
With the customer record with the OLD customer number being deleted and the customer record with the New customer number being updated from the OLD customer number
Here is my situation
There are records where the NEW customer number has been merged into another customer number and then THAT new custome number is then merged into yet another one
Here is an example
Old Cust # New Cust #
1 2
2 3
3 6
7 10
6 24
27 30
94 110
110 225
My aim is to pare this down to the following
Old Cust # New Cust #
1 24
7 10
27 30
94 225
I created queries to take the new customer number as the old customer number and see if that had been merged into another different new customer number I then took the results of that and repeated the process I then took the results of that and repeated the process I then took the results of that and repeated the process Etc.
It took 5 iterations, but the problem is - what happens when and if I need a 6th, and then a 7th
That's when I remembered reading about recursive sql
I found the following web sites
https://www.ibm.com/developerworks/ibmi/library/i-db2connectby/index.html
http://downloads.teradata.com/forum/database/help-with-recursive-query
From the last web site I created the following SQL - the problem was
that it was running for OVER 8 hours (281,000 records on the file
cstmerge)
I don't know if there is anything wrong with the below SQl I am hoping someone can see something that is wrong or can explain whats missing or needs changing
WITH RECURSIVE cte
(CMOLDCST#, CMNEWCST#, CMLSTCST#)
AS
(
SELECT CMOLDCST#, CMNEWCST#, CMNEWCST# as CMLSTCST#
FROM prodfa.cstmerge
WHERE CMOLDCST# <> CMNEWCST#
UNION ALL
SELECT t.CMOLDCST#, t.CMNEWCST#, cte.CMLSTCST#
FROM cte
INNER JOIN prodfa.cstmerge AS t
ON cte.CMOLDCST# = t.CMNEWCST#
WHERE t.CMOLDCST# <> t.CMNEWCST#
)
SELECT * FROM cte
ORDER BY 3,1
Alan Shore
E-mail : ASHORE@xxxxxxxx
Phone [O] : (631) 200-5019
Phone [C] : (631) 880-8640
'If you're going through hell, keep going.'
Winston Churchill
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