SELECT DISTINCT channel_code FROM customers AS t1 JOIN customer_contact_channels AS t2 ON t1.customer_id = t2.customer_id WHERE t1.customer_name = "Tillman Ernser"
Saluran kontak mana yang telah digunakan oleh pelanggan dengan nama "Tillman Ernser"?
CREATE TABLE customers (customer_id VARCHAR, customer_name VARCHAR); CREATE TABLE customer_contact_channels (customer_id VARCHAR)