Re: SQL update a numeric by replacing 2 digits with a constant

Charles,

In that case, why did it work for me? All my data had a value of less
than 10000000 for the cmcust field...


CREATE TABLE QTEMP/TEST1 (CMCUST DECIMAL ( 9, 0) NOT NULL WITH DEFAULT)

INSERT INTO QTEMP/TEST1 VALUES(rand() * 100000) (repeat as needed)




select cmcust, '50'||substr(cmcust, 3, 7) as x from test1

*CMCUST X *

84,655 50655

71,871 50871

21,131 50131

91,290 50290


update test1 set cmcust = '50'||substr(cmcust, 3, 7) (worked ok)


Regards,





Luis Rodriguez
IBM Certified Systems Expert — eServer i5 iSeries
--



On Tue, Dec 21, 2010 at 3:35 PM, Charles Wilt <charles.wilt@xxxxxxxxx>wrote:

The implicit casting done by the system, is equivalent to cast(cmcust
as char)...

The problem is that such a cast drops lead zeros, which screws up your
SUBSTR when the value of CMCUST is less than 10000000.

HTH,
Charles

On Tue, Dec 21, 2010 at 1:20 PM, Dan <dan27649@xxxxxxxxx> wrote:

I think there is some default casting going on here, as I'm just reading

up

on that. I am testing the following:

CAST( '50' || substr( digits( cmcust), 3, 7) AS DECIMAL(9,0))

and results so far look good.

Since doing an UPDATE with the original code didn't provide any

diagnostic

feedback, I constructed the following query:
select cmcust as orig_cmcust,
substr( cmcust, 3, 7 ) as substr_cmcust_3_7,
substr( digits( cmcust), 3, 7) as substr_digits_cmcust,
CAST( substr( digits( cmcust), 3, 7) AS DECIMAL(9,0)) as

CAST_cmcust

from Lib1/Customer

Results (best viewed in fixed font):
ORIG_CMCUST SUBSTR_CMCUST_3_7 SUBSTR_DIGITS_CMCUST CAST_CMCUST
5,086,931 86931 5086931 5,086,931
5,073,765 73765 5073765 5,073,765
5,073,858 73858 5073858 5,073,858
6,062,249 62249 6062249 6,062,249
9,113,707 13707 9113707 9,113,707

So, it appears that using a SUBSTR on a packed-decimal without an
intervening DIGITS causes havoc. The second column is a 7-character

result

with two blanks trailing the five digits. While I haven't determined WHY

it

does this, I believe I have determined how to resolve it.

Thanks,
- Dan

On Tue, Dec 21, 2010 at 12:38 PM, Alan Campin <alan0307d@xxxxxxxxx>

wrote:

I don't see how this would work at all if CMCUST is a packed 9,0. I

would

have converted CMCUST to a string, then done the substr and then cast

the

result back to a dec 9,0. Based on substringing a packed 9,0 I would

guess

the results could be anything.

On Tue, Dec 21, 2010 at 10:18 AM, Dan <dan27649@xxxxxxxxx> wrote:

The messed-up data I mentioned in my previous thread several minutes

ago

was
caused by:

Update Lib1/Customer Set cmcust = '50' || substr( cmcust , 3, 7 )

cmcust is a 9.0 packed decimal. The goal is to REPLACE the first two
digits
of cmcust with 50.

In another library I used this in, the update worked as expected.

However,

for reasons unknown to me, the update in this library replaced the 3rd

&

4th
digits of cmcust with 50. Any ideas?

FWIW, we just upgraded to V6R1 with cum PTF TL60215 applied. I've

been

out

of the OS admin side of things for too long to know whether that is a
recent
cum PTF.

TIA,
- Dan
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