Otestad men något sånt här med endast SQL:
MERGE INTO your_table dst
USING (
SELECT ROW_NUMBER() OVER (
PARTITION BY tDate, Product, Price, Quantity, BuySell
ORDER BY ID
) AS idx,
COUNT( CASE BuySell WHEN 'Buy' THEN 1 END ) OVER (
PARTITION BY tDate, Product, Price, Quantity
) AS num_buy,
COUNT( CASE BuySell WHEN 'Sell' THEN 1 END ) OVER (
PARTITION BY tDate, Product, Price, Quantity
) AS num_sell
FROM your_table
) src
ON ( src.ROWID = dst.ROWID AND src.idx <= LEAST( src.num_buy, src.num_sell ) )
WHEN MATCHED THEN
UPDATE SET Status = 'Matched';