vb+mssql查询问题2

比如
一个是用户列表
UserID
1
2
3
4

一个是记录列表(每个用户一天可能有多条数据)
UserID Day
1 2009-09-22
1 2009-09-22
1 2009-09-22

2 2009-09-22
2 2009-09-22
2 2009-09-22
2 2009-09-22

4 2009-09-22
4 2009-09-22

想要的结果是
1 3
2 4
4 2
可能有些用户没数据。该如何写查询语句呢？

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select userid,count(userid)
from 记录列表
group by userid

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引用

select a.UserId as UserId,b.i as i
from 用户列表 as a
inner join (select UserId,count(day) as i from 记录列表) as b
on a.UserId=b.UserId
order by a.UserId

好像不行呢
一个是用户列表
ID
1
2
3
4

一个是记录列表(每个用户一天可能有多条数据)
UserID Day
1 2009-09-22
1 2009-09-22
1 2009-09-22
1 2009-09-23

2 2009-09-22
2 2009-09-22
2 2009-09-22
2 2009-09-22

4 2009-09-22
4 2009-09-22

想要的结果是 当天每个用户的总数
1 3
2 4
4 2

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select d.id,count(*) as 数量
from (SELECT a.id ,b.day from a inner join b on a.UserId =b.UserId ) d
order by d.id

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SQL code

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