Need a Query to update....below are requirements

Question

Hi,
I need a query to update table xx_cc_audit. below are requirements.
In xx_cc_audit I have more than 1000 rows. In this table Column - contract_number is inserted as null for some rows.
I need a query to update this xx_cc_audit table which will replace null contract numbers with correct ones.
In table xx_cc_audit I have column - instance_id which is not null and not unique.(duplicate instance id's can be there).
With this instance_id i can get the contract_number from other table okc_k_headers_b .
I need a query to update xx_cc_audit table.
Presently what I'm doing :
Select XS.instance_id
FROM cs_incidents_all_b CS,xx_cc_audit XS
where XS.contract_number is null
AND XS.SR_NUMBER = CS.incident_number
AND XS.ACTIVITY_TYPE = 'TROUBLESHOOTING';
Note : The above query can give duplicate instance_id.
Say, above query results in 100rows.
I will copy any 1 instance_id in a paper and then pass it to below query.
SELECT contract_number
FROM okc_k_headers_b
WHERE id = (SELECT MAX(dnz_chr_id)
FROM okc_k_items
WHERE object1_id1 = TO_CHAR(144849056) --instance_id
AND jtot_object1_code = 'OKX_CUSTPROD'
AND object1_id2 = '#'
AND chr_id IS NOT NULL);
I'll get contract_number.
then i'll update xx_cc_audit table as below.
update      xx_cc_audit set contract_number = 1223464789 -- which i got as a result of above query
where contract_number is null
and instance_id = 144849056     --this i copied from paper, as mentioned above     ;
this will update my table.
I have more than 1000rows, so i need a query which will update 1000rows in 1 shot.
Please help me.
Thanks!...
Edited by: Kiran Sanga on Jul 20, 2009 2:15 AM

Answer 1

OK, so that means a maximum of 10 distinct IDs in okc_k_headers_b can be matched with xx_cc_audit xca.
That's a data issue for yourself that you'll need to work out, i.e, are you being too restrictive in any of the subqueries, particularly this one:
WHERE id = (
    SELECT MAX(dnz_chr_id)
      FROM okc_k_items
    WHERE object1_id1 IN (
      Select XS.instance_id
      FROM cs_incidents_all_b CS,xx_cc_audit XS
      where XS.contract_number is null
        AND XS.SR_NUMBER = CS.incident_number
        AND XS.ACTIVITY_TYPE = 'TROUBLESHOOTING')
  AND jtot_object1_code = 'OKX_CUSTPROD'
  AND object1_id2 = '#'
  AND chr_id IS NOT NULL)Edited by: SeánMacGC on Jul 20, 2009 3:37 AM
And here is a slight different version of the update that should perform a little better:
update xx_cc_audit xca set contract_number = (
  SELECT contract_number
    FROM okc_k_headers_b okhb
WHERE id IN (
    SELECT dnz_chr_id
      FROM okc_k_items
    WHERE object1_id1 IN (
      Select XS.instance_id
      FROM cs_incidents_all_b CS,xx_cc_audit XS
      where XS.contract_number is null
        AND XS.SR_NUMBER = CS.incident_number
        AND XS.ACTIVITY_TYPE = 'TROUBLESHOOTING')
  AND jtot_object1_code = 'OKX_CUSTPROD'
  AND object1_id2 = '#'
  AND chr_id IS NOT NULL)
  AND xca.instance_id = okhb.object1_id1
where contract_number is null;