Show the account id and name for each account with a transaction.
select t1.account_id, t2.account_name from financial_transactions as t1 join accounts as t2 on t1.account_id = t2.account_id
Also count the number of transactions for each of them.
select t1.account_id, t2.account_name, count(*) from financial_transactions as t1 join accounts as t2 on t1.account_id = t2.account_id group by t1.account_id
Which of them have at least 4 transactions?
select t1.account_id, t2.account_name from financial_transactions as t1 join accounts as t2 on t1.account_id = t2.account_id group by t1.account_id having count(*) >= 4