DB2 merge upsert gets 'Row not found for MERGE' error - db2

Question

I am trying to do a basic upsert on an iSeries db2 with the MERGE statement, similar to as described in Does DB2 have an "insert or update" statement? and http://db2performance.blogspot.com/2011/12/merge-make-your-upserts-quick.html. When executed, it gives me Row not found for MERGE. SQLSTATE=02000 instead of inserting the row. Since I have when not matched then insert in the statement, why will it return an error instead of inserting? I looked all over SO and didn't see this particular issue.
Here is the statement I'm using:
merge into UFDFTRN as T using (
select * from UFDFTRN
where DFCNO = 354 and DFINV = 1179 and DFLC = 1 and DFDATE = '2017-01-31'
and DFSPLT = 0 and DFSEQ = 100
) as S on (
T.DFCNO = S.DFCNO and T.DFINV = S.DFINV and T.DFDATE = S.DFDATE and
T.DFSPLT = S.DFSPLT and T.DFSEQ = S.DFSEQ
) when matched then
update set DFSEQ = 1000, DFTRAN = 0, DFITEM = 'F224', DFRITM = '0',
DFDESC = 'DAIRY VTM PREMIX', DFQTY = 3, DFUM = '',DESIQU = 0, DFRTQU = 3,
DFUPR = 0, DFCTUP = 0, DFUCST = 0, DFOUCST = 0, DFAMT = 0, DFOAMT = 0, DFCODE = '',
DFURAT = '', DFCGCD = '0', DFCTNO = 0, DFADJITM = '', DFADJPCT = 0, DFMNFITM = '',
DFMNFRAT = '', DFMNFQTY = '0', DFMNFTQTY = '0'
when not matched then
insert (DFCNO, DFINV, DFLC, DFDATE, DFSPLT, DFSEQ, DFTRAN, DFITEM, DFRITM, DFDESC,
DFQTY, DFUM, DFSIQU, DFRTQU, DFUPR, DFCTUP, DFUCST, DFOUCST, DFAMT, DFOAMT, DFCODE,
DFURAT, DFCGCD, DFCTNO, DFADJITM, DFADJPCT, DFMNFITM, DFMNFRAT, DFMNFQTY, DFMNFTQTY
) values (
354, 1179, 1, '2017-01-31', 0, 1000, 0, 'F224', '0', 'DAIRY VTM PREMIX', 3, '', 0,
3, 0, 0, 0, 0, 0, 0, '', '', '0', 0, '', 0, '', '', '0', '0'
)

Answer 1

It probably should look more like this:
merge into UFDFTRN as T using (
select 354 DFCNO, 1179 DFINV, 1 DFLC, '2017-01-31' DFDATE, 0 DFSPLT, 100 DFSEQ
, 'DAIRY VTM PREMIX' f1 -- all other columns you might need
from sysibm.sysdummy1
) as S
on (
T.DFCNO = S.DFCNO and T.DFINV = S.DFINV and T.DFDATE = S.DFDATE and
T.DFSPLT = S.DFSPLT and T.DFSEQ = S.DFSEQ
)
when matched then
update set T.DFSEQ = S.DFSEQ, T.DFTRAN = S.DFTRAN, -- etc. etc.
when not matched then
insert (DFCNO, DFINV, ... -- etc. etc.
) values (
S.DFSNO, S.DFINV, ..., S.F1, ...-- etc. etc.
)
PS. Not tested.

Answer 2

Mustaccio has the right format for the merge...
But as I commented, that's a really funny way to use merge.
Personally, for a 1 time thing, I would have just
update UFDFTRN
set (DFCNO, DFINV, DFLC, DFDATE, DFSPLT, DFSEQ, DFTRAN, DFITEM, DFRITM, DFDESC,
DFQTY, DFUM, DFSIQU, DFRTQU, DFUPR, DFCTUP, DFUCST, DFOUCST, DFAMT, DFOAMT, DFCODE,
DFURAT, DFCGCD, DFCTNO, DFADJITM, DFADJPCT, DFMNFITM, DFMNFRAT, DFMNFQTY, DFMNFTQTY
) = (
354, 1179, 1, '2017-01-31', 0, 1000, 0, 'F224', '0', 'DAIRY VTM PREMIX', 3, '', 0,
3, 0, 0, 0, 0, 0, 0, '', '', '0', 0, '', 0, '', '', '0', '0'
)
where DFCNO = 354 and DFINV = 1179 and DFLC = 1 and DFDATE = '2017-01-31'
and DFSPLT = 0 and DFSEQ = 100
And if that failed with record not found, simply changed the update to an insert
insert into UFDFTRN
(DFCNO, DFINV, DFLC, DFDATE, DFSPLT, DFSEQ, DFTRAN, DFITEM, DFRITM, DFDESC,
DFQTY, DFUM, DFSIQU, DFRTQU, DFUPR, DFCTUP, DFUCST, DFOUCST, DFAMT, DFOAMT, DFCODE,
DFURAT, DFCGCD, DFCTNO, DFADJITM, DFADJPCT, DFMNFITM, DFMNFRAT, DFMNFQTY, DFMNFTQTY
) values (
354, 1179, 1, '2017-01-31', 0, 1000, 0, 'F224', '0', 'DAIRY VTM PREMIX', 3, '', 0,
3, 0, 0, 0, 0, 0, 0, '', '', '0', 0, '', 0, '', '', '0', '0'
)

Answer 3

This use case is not unusual at all. This is the most basic use case for merge imo. You're trying to update or insert into 1 table. It really should be easier but the solution is to put any where clause in the on () portion of the statement and it starts working as expected. (worked db2 luw 10.5 at least.. I have the exact same situation) Merge apparently can't handle the using () portion's where clause. It only sees what's in on () portion for the update/insert criteria. Don't follow sysdummy1 answer as that isn't determining if the data actually exists in the target table it's just text. I don't want to write an insert and check failure because it will cause the app to throw an error and I really shouldn't have to trap the error and do that code if db2 has this feature.