如何获得唯一的名称的总和，同时按日期分组

Question

我使用Oracle 10g和我的登录用户

created    userid 
-------------------- ------ 
10-jul-2014 10:10:10 usr1 
10-jul-2014 10:12:10 usr2 
10-jul-2014 11:12:10 usr1 
10-jul-2014 12:12:10 usr3 
13-jul-2014 10:12:10 usr1 
13-jul-2014 11:12:10 usr2 

表

我期待的输出是

created   count(userid) 
-----------  ------------------ 
10-jul-2014  3 (3 unique users) 
13-jul-2014  2 (2 unique users) 

查询我想出了没有按预期工作

select trunc(created) cr, userid 
from loggedinusers 
group by trunc(created), userid 
order by trunc(created) asc; 

Answer 1

使用下面的查询

select trunc(created) cr, count(distinct userid) 
from loggedinusers 
group by trunc(created) 
order by trunc(created) asc; 

Answer 2

select trunc(created) cr, count(userid) as cnt 
from loggedinusers 
group by trunc(created) 
order by trunc(created) asc;