select c.id as id,
       coalesce(c.brand, p.brand) as brand,
       coalesce(c.name, p.name) as name,
       p.api_url,
       c.code as code,
       coalesce(c.price, p.price * (100 - c.discount) / 100) as price,
       p.type as type,
       p.subtype as subtype,
       coalesce(c.period, p.period) as period,
       c.ttl as ttl,
       p.schema as schema
  from product p
       join campaign c on (c.product=p.id)
 where c.not_before <= now()
       and c.not_after > now();