using MERGE in 9i

问题

I want to do something like this in 9i

MERGE INTO SAT_DEMANDS D
      USING (SELECT DISTINCT d1.PRODUCT_ID AS product_id, CA.CUST_ID as allocated_cust  
        FROM CDP_MPS_ALLOCATION CA, sat_demands d1
        WHERE substr(d1.product_id,1,instr(d1.product_id,'_VIRTUAL',1)-1) = ca.prod_id(+)) MC
        ON (D.PRODUCT_ID = MC.product_id AND D.CUSTOMER_ID = MC.allocated_cust)
        WHEN matched then 
        Update set D.alloc_cust_id_s = CASE WHEN mc.allocated_cust IS NULL THEN 'FREE'
                                       ELSE mc.allocated_cust||':'||'FREE'
                                       END;

Please help! Oracle 9i does not allow me to do this since it does not have when not matched. how do I achieve the same result in 9i?

回答1:

Using a rowid approach:

FOR r in (SELECT D.rowid, MC.allocated_cust FROM
           (SELECT DISTINCT d1.PRODUCT_ID AS product_id, CA.CUST_ID as allocated_cust  
               FROM CDP_MPS_ALLOCATION CA, sat_demands d1
             WHERE substr(d1.product_id,1,instr(d1.product_id,'_VIRTUAL',1)-1) = ca.prod_id(+)
            ) MC
            join SAT_DEMANDS D
            ON (D.PRODUCT_ID = MC.product_id AND D.CUSTOMER_ID = MC.allocated_cust)
         )
LOOP

        Update SAT_DEMANDS D
        set D.alloc_cust_id_s = CASE WHEN r.allocated_cust IS NULL THEN 'FREE'
                                     ELSE r.allocated_cust||':'||'FREE'
                                       END
        where rowid=r.rowid;
END LOOP;

回答2:

Oracle 9i does have the WHEN NOT MATCHED clause. You can't use update however with it.

In your case you don't need merge, UPDATE should do what you want:

UPDATE sat_demands d
   SET alloc_cust_id_s = nvl((SELECT mc.allocated_cust || ':FREE'
                               FROM mc
                              WHERE d.product_id = mc.product_id
                                AND d.customer_id = mc.allocated_cust),
                             'FREE')

来源：https://stackoverflow.com/questions/7266880/using-merge-in-9i