CREATE TABLE customer_orders (order_id NUMBER, customer_id NUMBER, order_status CLOB, order_date TIME, order_details CLOB)
CREATE TABLE customers (customer_id NUMBER, payment_method CLOB, customer_name CLOB, date_became_customer TIME, other_customer_details CLOB)
CREATE TABLE order_items (order_id NUMBER, product_id NUMBER, order_quantity CLOB)
CREATE TABLE products (product_id NUMBER, product_details CLOB)
CREATE TABLE addresses (address_id NUMBER, address_content CLOB, city CLOB, zip_postcode CLOB, state_province_county CLOB, country CLOB, other_address_details CLOB)
CREATE TABLE customer_addresses (customer_id NUMBER, address_id NUMBER, date_address_from TIME, address_type CLOB, date_address_to TIME)
CREATE TABLE customer_contact_channels (customer_id NUMBER, channel_code CLOB, active_from_date TIME, active_to_date TIME, contact_number CLOB)

Find the list of cities that no customer is living in.
SELECT city FROM addresses WHERE NOT city IN (SELECT DISTINCT t3.city FROM customers AS t1 JOIN customer_addresses AS t2 ON t1.customer_id = t2.customer_id JOIN addresses AS t3 ON t2.address_id = t3.address_id)
WITH "_u_0" AS (SELECT DISTINCT "t3"."city" FROM "customers" "t1" JOIN "customer_addresses" "t2" ON "t1"."customer_id" = "t2"."customer_id" JOIN "addresses" "t3" ON "t2"."address_id" = "t3"."address_id" GROUP BY "city") SELECT "city" FROM "addresses" LEFT JOIN "_u_0" "_u_0" ON "_u_0"."" = "city" WHERE "_u_0"."" IS NULL