Question

我正在尝试根据时间戳从表中获取最新记录。他是我写的查询：

SELECT DISTINCT
    [Year], 
    [Type],
    [Category],
    [AnnualCost],
    MAX([TimeStamp]) OVER (PARTITION BY [Year], [Type], [Category], [AnnualCost]) AS MaxTimeStamp
FROM 
    [PromOneSite].[Budgeting].[MISBasePrice]
WHERE
    Year = 2016
    AND category IN ('Leasing Office Desktop')
    AND TimeStamp IS NOT NULL

结果：

Year    Type                           Category                 AnnualCost   MaxTimeStamp
----------------------------------------------------------------------------
2016    Equipment Hardware Location    Leasing Office Desktop       750.00     2015-10-14 17:54:09.510
2016    Equipment Hardware Location    Leasing Office Desktop       850.00     2015-10-14 17:54:20.630

我得到了这两个不同数量和不同时间戳的记录。我知道这是因为我在查询中添加了不同的内容，它也为我带来了明显的Annualcost。但如果没有明显的差异，我会获得大约30多个重复记录

在这种情况下，如何只获得一条带有最新时间戳的记录。

提前致谢

Answer 1

select * from 
(  SELECT [Year]
         ,[Type]
         ,[Category]
         ,[AnnualCost]
         ,[TimeStamp] as MaxTimeStamp
         ,row_number() over (partition by [Year], [Type], [Category] order by [TimeStamp] desc ) as rn 
     FROM [PromOneSite].[Budgeting].[MISBasePrice]
    where Year = 2016
      and category IN ('Leasing Office Desktop')
      and TimeStamp IS Not Null 
) tt
where tt.rn = 1

Answer 2

SELECT top 1 distinct [Year] ,[Type] ,[Category] ,[AnnualCost] ,max([TimeStamp]) over (partition by [Year],[Type],[Category], [AnnualCost] ) as MaxTimeStamp FROM [PromOneSite].[Budgeting].[MISBasePrice] where Year = 2016 and category IN ('Leasing Office Desktop')  order by [TimeStamp] DESC

如何根据时间戳从SQL Server表中获取最新记录

2 个答案: