How many transaction does account with name 337 have?
SELECT count(*) FROM Financial_transactions AS T1 JOIN Accounts AS T2 ON T1.account_id  =  T2.account_id WHERE T2.account_name  =  "337"
transaction count for a specific account name involves JOIN operation between Financial_transactions and Accounts tables on account_id; account with name 337 refers to WHERE condition T2.account_name = '337';