Update with correlated subquery

Question

Hi,
I have the following SQL update statement:
update temp_input_sms b
set (b.provider_id,b.region_id)=
     (select provider_id,region_id
     from
     select a.PROVIDER_ID,a.REGION_ID,row_number() over (order by fraud) rn
     from icdm.smsc_lookup a
     where sysdate>=a.VALID_FROM and sysdate<a.VALID_TO
          and b.user_summarisation like a.SMSC_CODE_LIKE
     ) where rn=1)
The problem is that there are two nested subqueries on the right side of the set clause, and in the inner subquery the 'b.user_summarisation' column is not available.
Could anyone suggest a workaround for this problem?
Thanks.
Viktor

Answer 1

possible workaround:
update temp_input_sms c
set    (c.provider_id, c.region_id) =
       (select d.provider_id, d.region_id
        from   (select a.provider_id, a.region_id, smsc_code_like,
                       row_number () over
                         (partition by a.smsc_code_like
                          order     by a.fraud) rn
                from   smsc_lookup a, temp_input_sms b
                where  sysdate >= a.VALID_FROM
                and    sysdate < a.VALID_TO
                and    b.user_summarisation like a.SMSC_CODE_LIKE) d
        where rn=1
        and   c.user_summarisation like d.smsc_code_like)
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