what are the names of the payment method of customers who have both mailshot in 'Order' outcome and mailshot in 'No response' outcome.
select t2.customer_name, t2.payment_method from mailshot_customers as t1 join customers as t2 on t1.customer_id = t2.customer_id where t1.outcome_code = 'Order' intersect select t2.customer_name, t2.payment_method from mailshot_customers as t1 join customers as t2 on t1.customer_id = t2.customer_id where t1.outcome_code = 'No Response'
How many customers pay by Credit card?
select count ( * ) from customers where payment_method = "Credit Card"
which customers pay with debit card?
select * from customers where payment_method = "Direct Debit"