Show the names of all customers.
select customer_name from customers
Who has an order in completed status?
select t1.customer_name from customers as t1 join customer_orders as t2 on t1.customer_id = t2.customer_id where t2.order_status_code = 'Completed'
Who has an order in part status?
select t1.customer_name from customers as t1 join customer_orders as t2 on t1.customer_id = t2.customer_id where t2.order_status_code = 'Part'
Who has both?
select t1.customer_name from customers as t1 join customer_orders as t2 on t1.customer_id = t2.customer_id where t2.order_status_code = 'Completed' intersect select t1.customer_name from customers as t1 join customer_orders as t2 on t1.customer_id = t2.customer_id where t2.order_status_code = 'Part'