需要选择部门最新登记的人加入

Question

人的时候：

Id Name 
1 Anton 
2 Ib 
3 Knud 
4 Hans 

报名：

Id PersonId Status DateTime  Department 
5 1   1  11-1-2013 10:00 1 
6 1   0  10-1-2013 09:00 1 
7 1   2  10-1-2013 14:05 1 
8 1   2  09-1-2013 09:00 1 
9 2   2  09-1-2013 09:00 2 
10 3   2  09-1-2013 09:00 3 
11 4   2  10-1-2013 17:00 1 

，我需要选择最新的注册（由人）一天（10-1-2013）部门1

预期产出：

Name R.Id P.Id Status DateTime  Department 

Anton 7  1  2  10-1-2013 14:05 1 
Hans 11  4  2  10-1-2013 17:00 1 

Answer 1

我觉得你只是想这样的：

select top 1 p.name, r.id, p.id, r.status, r.datetime, r.department 
from registration r join 
    person p 
    on r.personid = p.personid 
where department = 1 and cast(daTetime as date) = '10-1-2013' 
order by datetime desc 

按部门最新的注册，而不是人。这只是使用where子句按日期和部门进行筛选，按datetime列排序并选择第一个。

为了让所有的人：

select p.name, r.id, p.id, r.status, r.datetime, r.department 
from (select r.*, row_number() over (partition by person order by datetime desc) as seqnum 
     from registration r 
     where department = 1 and cast(daTetime as date) = '10-1-2013' 
    ) r join 
    person p 
    on r.personid = p.personid 
where seqnum = 1 
order by datetime desc