Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE accounts ( account_id number, customer_id number, account_name text, other_account_details text )
TABLE: CREATE TABLE customers ( customer_id number, customer_first_name text, customer_last_name text, customer_address text, customer_phone text, customer_email text, other_customer_details text )
TABLE: CREATE TABLE financial_transactions ( transaction_id number, previous_transaction_id number, account_id number, card_id number, transaction_type text, transaction_date time, transaction_amount number, transaction_comment text, other_transaction_details text )
TABLE: CREATE TABLE customers_cards ( card_id number, customer_id number, card_type_code text, card_number text, date_valid_from time, date_valid_to time, other_card_details text )

### Question ###
Return the average transaction amount, as well as the total amount of all transactions.

### Accurate SQL ###

SELECT AVG(transaction_amount), SUM(transaction_amount) FROM financial_transactions