caching the results is one solution which could help but this time some other factors make things complicated... well, i still can work on that...
subquery got involved, because i could not manage to work with GROUP BY and ORDER BY in the same query.. regardless of what ORDER BY dictates, GROUP BY returns same results....
i think, one of the bad things i do in here is ordering by impression to provide rotation...
ok, i guess it's better to get back simple javascript banner rotator for server's health
