Question: Show the id and details of the investor that has the largest number of transactions.
Schema: create table transactions (investor_id varchar, PRIMARY KEY (investor_id)); create table investors (investor_details varchar, investor_id varchar, PRIMARY KEY (investor_details))
SQL: select t2.investor_id, t1.investor_details from investors as t1 join transactions as t2 on t1.investor_id = t2.investor_id group by t2.investor_id order by count(*) desc limit 1