Return the names and ids of each account, as well as the number of transactions.
SELECT T2.account_name ,  T1.account_id ,  count(*) FROM Financial_transactions AS T1 JOIN Accounts AS T2 ON T1.account_id  =  T2.account_id GROUP BY T1.account_id
names and ids of each account refers to account_name and account_id; number of transactions refers to COUNT(*); JOIN operation is used to combine rows from two or more tables based on a related column between them, in this case, account_id;