What are the different account ids that have made financial transactions, as well as how many transactions correspond to each?
SELECT account_id ,  count(*) FROM Financial_transactions GROUP BY account_id
SELECT account_id ,  count(*) FROM Financial_transactions GROUP BY account_id
[{'account_id': 1, 'count(*)': 1}, {'account_id': 3, 'count(*)': 1}, {'account_id': 4, 'count(*)': 1}, {'account_id': 5, 'count(*)': 1}, {'account_id': 6, 'count(*)': 1}, {'account_id': 8, 'count(*)': 1}, {'account_id': 9, 'count(*)': 1}, {'account_id': 10, 'count(*)': 2}, {'account_id': 11, 'count(*)': 1}, {'account_id': 12, 'count(*)': 1}, {'account_id': 13, 'count(*)': 1}, {'account_id': 14, 'count(*)': 1}, {'account_id': 15, 'count(*)': 2}]