CREATE TABLE customers (customer_name VARCHAR, customer_id VARCHAR)
CREATE TABLE customer_contact_channels (active_from_date VARCHAR, customer_id VARCHAR, channel_code VARCHAR)

Find the name and active date of the customer that use email as the contact channel.
SELECT t1.customer_name, t2.active_from_date FROM customers AS t1 JOIN customer_contact_channels AS t2 ON t1.customer_id = t2.customer_id WHERE t2.channel_code = 'Email'
SELECT "t1"."customer_name", "t2"."active_from_date" FROM "customers" AS "t1" JOIN "customer_contact_channels" AS "t2" ON "t1"."customer_id" = "t2"."customer_id" AND "t2"."channel_code" = 'Email'