Show the name and phone for all customers.
select customer_name, customer_phone from customers
Only show the results for those customers with a mailshot.
select t1.customer_name, t1.customer_phone from customers as t1 join mailshot_customers as t2 on t1.customer_id = t2.customer_id
Among those, how about the results for customers also with the outcome code 'No Response'.
select t1.customer_name, t1.customer_phone from customers as t1 join mailshot_customers as t2 on t1.customer_id = t2.customer_id where t2.outcome_code = 'No Response'