Example: local aliases

#
# mysql config file for 
local(8) 
aliases(5) lookups
#

# The user name and password to log into the mysql server.
user = someone
password = some_password

# The database name on the servers.
dbname = customer_database

# For Postfix 2.2 and later The SQL query template.
# See 
mysql_table(5) for details.
query = SELECT forw_addr FROM mxaliases WHERE alias='%s' AND status='paid'

# For Postfix releases prior to 2.2. See 
mysql_table(5) for details.
select_field = forw_addr
table = mxaliases
where_field = alias
# Don't forget the leading "AND"!
additional_conditions = AND status = 'paid'