CREATE TABLE Financial_transactions (transaction_type VARCHAR, transaction_amount INT)

What is the transaction type that has processed the greatest total amount in transactions?
SELECT transaction_type FROM Financial_transactions GROUP BY transaction_type ORDER BY SUM(transaction_amount) DESC LIMIT 1
SELECT "transaction_type" FROM "Financial_transactions" GROUP BY "transaction_type" ORDER BY SUM("transaction_amount") DESC NULLS LAST LIMIT 1