Please list just Tillman Ernsers contact channel
SELECT DISTINCT channel_code FROM customers AS t1 JOIN customer_contact_channels AS t2 ON t1.customer_id   =   t2.customer_id where customer_name  =  "Tillman Ernser"
list Tillman Ernser's contact channel refers to SELECT DISTINCT channel_code; joining customers with customer_contact_channels on customer_id; filtering by customer_name = 'Tillman Ernser';