PL/SQL: Fast insert based on 2nd table

I have three tables:
TransactionTable contains product_id, DateSold - has a couple million records
ExceptionTable contains product_id and E_Code - empty to start, will be populated based on:
ProductTable contains product_id, myCondition, LastChangeDate

ProductTable is NOT unique for product_id but is unique with product_id & LastChangeDate
TransactionTable can have multiple records for product_id on the same DateSold

I need to go through the TransactionTable, get the product_id, look into the ProductTable. If the Product_ID exists in the ProdcutTable
where the ProductTable Mycondition ='X'
I have to get the one record from the ProductTable where the maximum LastChangeDate is less than the DateSold and use this for the above comparison

The way I'm doing it now is sending each TransactionTable.product_id and the DateSold to the following and then updating the ExceptionTable where this returns 'X':

SELECT myCondition INTO tmpReturn
        FROM
            (
             SELECT myCondition
             FROM ProductTable
             WHERE ProductTable.product_id = <Passed product_id>
                 AND ProductTable.LastChangeDate = (SELECT MAX(LastChangeDate)
                                         FROM  ProductTable
                                         WHERE ProductTable.product_id = <Passed product_id>
                                             AND ProductTable.LastChangeDate <= (<Passed DateSold>))
                 AND ROWNUM = 1
            );

        CASE WHEN tmpReturn = 'X'
             THEN tmpReturn := 'Y';
             ELSE tmpReturn := 'N';
        END CASE;

       RETURN tmpReturn;

Is there a better/faster way to do this?
GNOVAKAsked:
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slightwv (䄆 Netminder)Connect With a Mentor Commented:
Try row_number.

Something like:
select myCondition from (
SELECT myCondition, row_number() over(partition by product_id order by lastchangedate desc) myrn FROM ProductTable where...
)
where myrn=1
0
 
awking00Commented:
Can you provide some sample data and your expected output?
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