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]