2006 MySQL server has gone away
in:
[select b.banners_id, b.expires_date, b.expires_impressions,
sum(bh.banners_shown) as banners_shown
from banners b, banners_history bh
where b.status = 1
and b.banners_id = bh.banners_id
group by b.banners_id, b.expires_date, b.expires_impressions]