MySQL GROUP_CONCAT Emails

#take a table of email addresses [table: alias; fields: domain, address, goto] and generate a list of email settings for each domain
select domain, group_concat(case when address != goto then concat(address, ' -> ', goto) when address = goto then address end order by address separator ', ') from alias group by domain;

#generates a result like
#| example.com    | user@example.com, info@example.com -> user@example.com |