Merge with multiple records at once
Is this the right ? from my side, the results are the same...
MERGE dbo.Transactions AS T
        USING (SELECT s.transactionID,s.transactionDate,s.productID,s.orderID,s.qty,s.unitPrice FROM dbo.Staging as s) AS s
        ON (t.transactionID = s.transactionID)
        WHEN MATCHED THEN
        UPDATE  SET 
                transactionDate = s.transactionDate,
                productId = s.productId,
                ReferenceOrderID=s.orderId,
                qty = s.qty,
                ActualCost = s.unitPrice        
    
        WHEN NOT MATCHED THEN
        INSERT (transactionID,transactionDate,productId,ReferenceOrderID,qty,ActualCost)     
        VALUES (s.transactionID, s.transactionDate,s.productId,s.orderId,s.qty,s.unitPrice);