需要選擇部門最新登記的人加入

Question

人的時候：

Id Name 
1 Anton 
2 Ib 
3 Knud 
4 Hans 

報名：

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 

，我需要選擇最新的註冊（由人）一天（10-1-2013）部門1

預期產出：

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

我覺得你只是想這樣的：

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 

按部門最新的註冊，而不是人。這只是使用where子句按日期和部門進行篩選，按datetime列排序並選擇第一個。

爲了讓所有的人：

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