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 Customers_cards ( card_type_code VARCHAR, card_id VARCHAR )
TABLE: CREATE TABLE Financial_transactions ( card_id VARCHAR )

### Question ###
Show the card type codes and the number of transactions.

### Accurate SQL ###

SELECT T2.card_type_code, COUNT(*) FROM Financial_transactions AS T1 JOIN Customers_cards AS T2 ON T1.card_id = T2.card_id GROUP BY T2.card_type_code