V9内的 SUM统计字段和
$item->get_one(array('user_id'=>918018601),'sum(`price`) AS num');;
V9内的 COUNT统计条数
$item->count();
排序
$where="`user_id`='$user_id' AND `chuchuang`!=2 AND `status`=0 ";
$arr_item=$chuchuang_list->select($where, '*','0,200','chuchuang desc,xiajia_time asc');
随机排序
$where=" `user_id`='$user_id' ";
$item_list=$item->select($where,'*','0,5','rand()');