邀请好友注册满足条件可获得奖品：统计领奖情况
奖励条目表 award_item：
注册记录表 award_reg_record：
领取奖品记录表 award_get_record：
统计某个任务下满足了领奖条件，但未领奖的人列表及其邀请的好友人数：
not exist方式效率高：
select user_id, count(new_user_id) from award_reg_record arrwhere not exists (select user_id from award_get_record agr where agr.user_id=arr.user_id and agr.item_id=101)group by user_idhaving count(*) > 5
select user_id, count(new_user_id) from award_reg_record arrwhere user_id not in (select user_id from award_get_record agr where agr.item_id=101)group by user_idhaving count(*) > 5
