CREATE TABLE customers (email_address VARCHAR2, phone_number VARCHAR2, customer_id VARCHAR2)
CREATE TABLE complaints (email_address VARCHAR2, phone_number VARCHAR2, customer_id VARCHAR2)

Find the email and phone number of the customers who have never filed a complaint before.
SELECT email_address, phone_number FROM customers WHERE NOT customer_id IN (SELECT customer_id FROM complaints)
SELECT "email_address", "phone_number" FROM "customers" WHERE NOT "customer_id" IN (SELECT "customer_id" FROM "complaints")