从数据库中挑选出1个结果

Question

问题： 我通过在不同的表上应用多个连接来从sql server填充asp.net报告。它可以工作，但是在一个问题的地方，我会通过单元格no的帮助选择PoliceStation名称。问题是1个小区没有可以是许多警察局，所以它挑选每个警察的名字并在报告中显示它。我只想要一个警察局名称，我需要从PoliceStations表

查询：

SELECT [ID]
      ,LEFT(REPLACE(convert(varchar, CmsSMSDb.dbo.SendMessages.SendingDateTime, 113), ' ','/'), 11) + ' ' +
       RIGHT(REPLACE(convert(varchar, CmsSMSDb.dbo.SendMessages.SendingDateTime, 113), ' ','/'), 12)
      as SendingDateTime
      ,[ToMobileNo]
      ,[Message]
      ,Designations.Name as [ToDesignation]
      FROM [CmsSMSDb].[dbo].[SendMessages] 
      inner join 
      CPOCMS.dbo.Designations
      ON CPOCMS.dbo.Designations.MobileNo = CmsSMSDb.dbo.SendMessages.ToMobileNo
      where Convert(date,CmsSMSDb.dbo.SendMessages.SendingDateTime)>= @DateFrom 
      AND 
      Convert(date,CmsSMSDb.dbo.SendMessages.SendingDateTime)<= @DateTo


      Union All

      SELECT [ID]
      ,LEFT(REPLACE(convert(varchar, CmsSMSDb.dbo.SendMessages.SendingDateTime, 113), ' ','/'), 11) + ' ' +
       RIGHT(REPLACE(convert(varchar, CmsSMSDb.dbo.SendMessages.SendingDateTime, 113), ' ','/'), 12)
      as SendingDateTime
      ,[ToMobileNo]
      ,[Message]
      ,'SDpo'+' '+CPOCMS.dbo.PoliceStations.PsName as [ToDesignation]
      From [CmsSMSDb].[dbo].[SendMessages] 
      inner join CPOCMS.dbo.PoliceStations
      ON CPOCMS.dbo.PoliceStations.sDpo_ContactNo = SendMessages.ToMobileNo
      where Convert(date,CmsSMSDb.dbo.SendMessages.SendingDateTime)>= @DateFrom 
      AND 
      Convert(date,CmsSMSDb.dbo.SendMessages.SendingDateTime)<= @DateTo
      order by SendMessages.ID

数据库结构：

Answer 1

只需使用这样的TOP子句。

SELECT TOP 1 ColumnA,
       ...,
...
...
..