dbpath = /etc/postfix/private/mail.sqlite
query = SELECT AL.aliasTarget FROM Alias AS AL
	JOIN Address AS AD ON AL.aliasNum=AD.addNum
	JOIN Domain AS D1 ON AD.addDomNum=D1.domNum
	WHERE AD.addLocalpart IS '%s'
	AND D1.domName IS 'myhostname.example.org'
	AND AL.active!=0;

# Note the hardcoded value of $myhostname.