14 database programmabillity

CREATE PROCEDURE usp_transfer_money(from_account_id INT,to_account_id INT,money_amount DECIMAL(19,4))
BEGIN
		START TRANSACTION;
        IF((SELECT id FROM ACCOUNTS WHERE id=from_account_id) IS NULL OR (SELECT id FROM ACCOUNTS WHERE id=to_account_id) IS NULL
        OR money_amount<0 OR (SELECT balance FROM accounts WHERE id=from_account_id)-money_amount<0 OR from_account_id=to_account_id
        )
        THEN
        ROLLBACK;
        ELSE
        UPDATE accounts as a_from
		SET balance=balance-money_amount
		WHERE a_from.id=from_account_id;

		UPDATE accounts as a_to
		SET balance=balance+money_amount
		WHERE  a_to.id=to_account_id;

        COMMIT;
        END IF;



END