What are the the full names and ids for all customers, and how many accounts does each have?
SELECT T1.customer_id ,  T2.customer_first_name ,  T2.customer_last_name ,  count(*) FROM Accounts AS T1 JOIN Customers AS T2 ON T1.customer_id  =  T2.customer_id GROUP BY T1.customer_id
full names = customer_first_name + customer_last_name; ids for all customers = customer_id; how many accounts does each have = COUNT(*) GROUP BY customer_id;