What Release you are on? The hierarchical query clause (Start with ...
connect by, Connect_By_Root and Connect_By_isLeaf) were introduced with
Technology Refresh in Release 7.1.
May be you are missing some PTF.
I run the source code I provided this morning on an 7.3 System without any
problems.
Just try to run a very basic statement with START WITH ... CONNECT BY. Just
to check whether you can use the hierarchical query clause.
Something like this:
Select *
From yourTable
Start with CMOldCst# = AspecificCustNo CONNECT BY Prior CMNewCst# =
CMOldCst#.
BTW I've written an article in 2011 about the Hierarchical Query Clause for
DeveloperWorks.
https://www.ibm.com/developerworks/ibmi/library/i-db2connectby/index.html
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: Donnerstag, 3. Mai 2018 14:45
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Subject: RE: Recursive SQL queries
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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