select *, (6371*acos(cos(radians())*cos(radians(latitude))*cos(radians(longitude)-radians())+sin(radians())*sin(radians(latitude)))) AS distance from g5_shop_item a, g5_shop_category b where (a.ca_id = b.ca_id and a.it_use = 1 and b.ca_use = 1) order by FIELD(it_premium, 1, 0), distance asc, it_order, it_id desc limit 40, 20