## count 与 distinct 联合使用 ~~~ $onlineNum = BraceletInformation::where($where)->distinct()->recycle()->count('uid'); ~~~ 上面的SQL语句为： ``` select count(distinct `uid`) as aggregate from `my8_bracelet_information` where (`date` = 20140428 and `business_id` = 1) and `is_recycle` = 0 ```