SQL - 最後日期時間

Question

我有選擇

select FisrtTable.[Date and Time],FisrtTable.[New Value],SecondTable.[Registering Date] 
from FisrtTable 
join SecondTable 
on FisrtTable.[New Value] = SecondTable.[New Value] 
where SecondTable.[Registering Date] >= '26-05-2015 0:00' 

我需要選擇通過[新值]檢索過去的日期時間，我有

但我想只有通過時間的最後一行

Answer 1

使用下面的查詢。

with cte_1 
as 
(select FisrtTable.[Date and Time],FisrtTable.[New Value],SecondTable.[Registering Date], 
     ROW_NUMBER()OVER(PARTITION BY FisrtTable.[New Value] ORDER BY FisrtTable.[Date and Time] desc) RNO 
from FisrtTable 
join SecondTable 
on FisrtTable.[New Value] = SecondTable.[New Value] 
where SecondTable.[Registering Date] >= '26-05-2015 0:00') 

SELECT [Date and Time],[New Value],[Registering Date] 
FROM cte_1 
WHERE RNO=1 

Answer 2

Simply選擇TOP 1記錄ordering整個結果DESC

Select 
top 1 st.datefield, st.* 
from SomeTable st 
Order by st.datefield desc