Update customer/order email addresses in test environment database (prevent to accidentally send test emails to real customers)

update_emails.sql

## Update order email addresses ##
UPDATE `sales_flat_order`
SET `customer_email` = CONCAT('test__', `customer_email`)
WHERE `customer_email` NOT IN ('email@domain.com', 'email2@domain.com')
AND `customer_email` NOT LIKE 'test__%';

## Update customer email addresses ##
UPDATE `customer_entity`
SET `email` = CONCAT('test__', `email`)
WHERE `email` NOT IN ('email@domain.com', 'email2@domain.com')
AND `email` NOT LIKE 'test__%';

How about newsletter subscribers?

UPDATE `newsletter_subscriber`
SET `subscriber_email` = CONCAT('test__', `subscriber_email`)
WHERE `subscriber_email` NOT IN ('email@domain.com', 'email2@domain.com')
AND `subscriber_email` NOT LIKE 'test__%';