with p as (select id,userid,domain_id,url,active from pages), 
     d as (select id,domain from valid_domains), 
     u as (select id,username from user_data) 

select p.url,d.domain,u.username from p,d,u 
where p.domain_id=d.id and p.userid=u.id and p.active order by p.url;