picking data to the right or left of a character

Try this:
...
regexp_substr(customer,'^[0-9]+') chain,
regexp_substr(customer,'[0-9]+$') customer,
...

are the portions you're interested in always 4 characters?

SELECT SUBSTR(custno, 1, 4) chain,
       SUBSTR(custno, -4) customer,
       rep "ROUTE",
       itmnum "ITEM",
       qty "QTY",
       TO_CHAR(SYSDATE, 'yyyymmdd') ship_date
  FROM credit_imports

http:#a39848517   assumes your data is always numeric.  If that's not the case and the data might not be 4 characters then try this..

SELECT REGEXP_SUBSTR(custno, '^[^- ]+') chain,
       REGEXP_SUBSTR(custno, '[^- ]+$') customer,
       rep "ROUTE",
       itmnum "ITEM",
       qty "QTY",
       TO_CHAR(SYSDATE, 'yyyymmdd') ship_date
  FROM credit_imports

added more data.

When customer starts with 2 or 4, it should stay as is. another way to decipher if it's exactly 5 characters long like the 24568 example below

TABLE

  CREATE TABLE CREDIT_IMPORTS 
   (	XDATE VARCHAR2(20 BYTE), 
	REP VARCHAR2(200 BYTE), 
	ITMNUM VARCHAR2(20 BYTE), 
	QTY VARCHAR2(20 BYTE), 
	CUSTNO VARCHAR2(20 BYTE), 
	CHAIN VARCHAR2(20 BYTE), 
	STATUS VARCHAR2(3 BYTE)
   ) 

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Insert into CDC.CREDIT_IMPORTS (XDATE,REP,ITMNUM,QTY,CUSTNO,CHAIN,STATUS) values ('20140213','90','456','5','7603 15','0',null);
Insert into CDC.CREDIT_IMPORTS (XDATE,REP,ITMNUM,QTY,CUSTNO,CHAIN,STATUS) values ('20140213','90','456','5','7603-15','0',null);
Insert into CDC.CREDIT_IMPORTS (XDATE,REP,ITMNUM,QTY,CUSTNO,CHAIN,STATUS) values ('20140213','90','456','5','25468','0',null);
Insert into CDC.CREDIT_IMPORTS (XDATE,REP,ITMNUM,QTY,CUSTNO,CHAIN,STATUS) values ('20140213','90','456','5','1820 - 54','0',null);
Insert into CDC.CREDIT_IMPORTS (XDATE,REP,ITMNUM,QTY,CUSTNO,CHAIN,STATUS) values ('20140213','90','456','5','26451','0',null);

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select qry

select 
CHAIN,
CUSTNO,
REP,
ITMNUM,
QTY,
XDATE
from credit_imports;

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current results

CHAIN	CUSTNO  	REP	ITEM	QTY	XDATE
0	7603 15		90	456	5	20140213
0	7603-15		90	456	5	20140213
0	24568		90	456	5	20140213
0	1820 - 54	90	456	5	20140213
0	26451		90	456	5	20140213

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Expected results

CHAIN	CUSTNO  	REP	ITEM	QTY	XDATE
7603	15		90	456	5	20140213
7606	15		90	456	5	20140213
0	24568		90	456	5	20140213
1820	54		90	456	5	20140213
0	26451		90	456	5	20140213

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also,

if chain has data value other than 0, leave untouched.. see below what happens.

good


bad

In the future you will get your answer a lot faster if you provide the exact requirements.

See if this works for you (I used sdstuber's regex just in case it isn't just numbers):
...
case when chain = '0' and substr(custno,1,1) in ('2','4') then chain else  REGEXP_SUBSTR(custno, '^[^- ]+') end chain,
case when chain = '0' and substr(custno,1,1) in ('2','4') then custno else  REGEXP_SUBSTR(custno, '[^- ]+$') end custno,
...

it's on the right path, it fixes chain / cust when cust has a combo like '7620 - 190'

but when my chain is setup the correct way '7620' and custno 190.. I get 190 for both

Current Results using slightwv last suggestion

190	190	100	3160	12	20140210
190	190	100	3161	12	20140210

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original data

7620	190	100	3160	12	20140210
7620	190	100	3161	12	20140210

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I am looking for the data to stay the same since it is already in the format that I need it

i tried this exactly

WITH Q AS (select
case when chain = '0' and substr(custno,1,1) in ('2','4','7') then chain else  REGEXP_SUBSTR(custno, '^[^- ]+') end chain,
case when chain = '0' and substr(custno,1,1) in ('2','4','7') then custno else  REGEXP_SUBSTR(custno, '[^- ]+$') end custno,
  REP "ROUTE",
  ITMNUM "ITEM",
  QTY "QTY",
  to_char(sysdate, 'yyyymmdd') SHIP_DATE
from credit_imports)

select * from Q where custno like '%190%';

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I am also getting records like this

0      7606-1570      30      1031      12      20140210
0      7606-1570      30      1032      12      20140210
0      7606-1570      30      1203      12      20140210
0      7606-1570      30      1206      12      20140210
0      7606-1570      30      1208      12      20140210

>>it's on the right path, it fixes chain / cust when cust has a combo like '7620 - 190'
>>but when my chain is setup the correct way '7620' and custno 190.. I get 190 for both

Please add actual insert statements to the sample above.  Just 'guessing' I cannot reproduce the results you posted.

Please see attached file
ee1.sql

for that row, chain 0, custno 26290.

 testing now

that looks good so far.

I will test in the AM with a full days worth of data.  full day worth of data will process about 9k rows for this process.

thanks for the help. always appreciated.

Thank you sir, worked perfectly