Show the first name, last name, and phone number for all customers.
select customer_first_name, customer_last_name, phone_number from customers
How about those with an account?
select t1.customer_first_name, t1.customer_last_name, t1.phone_number from customers as t1 join accounts as t2 on t1.customer_id = t2.customer_id
Show their distinct information.
select distinct t1.customer_first_name, t1.customer_last_name, t1.phone_number from customers as t1 join accounts as t2 on t1.customer_id = t2.customer_id