获取从唯一的记录表中​​的SQL Server最小的日期

Question

我有表说VendorReport在此表中，我有三列ID，PrefixId，在我的表Download_date 数据如下

ID  PrefixId Download_date 

1 VIS017 28-09-2012 
2 VIS028 29-09-2012 
3 VIS035 29-09-2012 
4 VIS028 30-09-2012 
5 VIS028 29-09-2012 
6 VIS028 01-10-2012 
7 VIS025 30-09-2012 

我想要的如下所示，具有最小日期的独特PrefixId记录

1 VIS017 28-09-2012 
2 VIS028 29-09-2012 
3 VIS035 29-09-2012 
4 VIS025 30-09-2012 

所以我试过这个查询，但没有得到预期的结果。

select VendorReport.PrefixId,VendorReport.Download_Date from VendorReport 
join (select PrefixId, MIN(Download_Date) d_date from VendorReport group by PrefixId) t2 on VendorReport.PrefixId= t2.PrefixId order by VendorReport.Download_Date asc 

Answer 1

目前尚不清楚你想要得到什么。希望这将有助于：

WITH T AS 
(
select 
    VendorReport.*, 
    ROW_NUMBER() OVER (PARTITION BY PrefixID 
         ORDER BY Download_date, ID) as RowNum 
from VendorReport 
) 
SELECT ID,PrefixId, Download_date 
FROM T 
WHERE RowNum=1 
Order by Download_Date DESC 

SQLFiddle demo

Answer 2

试试这个..............

select Row_number() over (order by x.Download_date),x.PrefixId,x.Download_date 
(
select PrefixId,Min(Download_date) Download_date 
from 
VendorReport 
group by Prefixid 
) x 

Answer 3

在这里你去

create table #VendorReport(
ID int, 
PrefixId nvarchar(50), 
Download_date datetime 
) 


insert into #VendorReport values(1,'IS017','2012-09-28'); 
insert into #VendorReport values(2,'IS028','2012-09-29'); 
insert into #VendorReport values(3,'IS035','2012-09-29'); 
insert into #VendorReport values(4,'IS028','2012-09-30'); 
insert into #VendorReport values(5,'IS028','2012-09-29'); 
insert into #VendorReport values(6,'IS028','2012-10-01'); 
insert into #VendorReport values(7,'IS025','2012-09-30'); 

select * from #VendorReport 
select ROW_NUMBER() OVER(ORDER BY PrefixId) as Id, PrefixId, min(Download_date) as Download_date from #VendorReport group by PrefixId 


drop table #VendorReport 

Answer 4

我在SQL Server的新 请试试这个

select prefixId,min(download_date) as download_date from #abc group by prefixId order by prefixId asc