SQL：选定的日期超出范围

Question

我有一个查询，它返回行创建时的最新日期。日期为“2010-02-03”

SELECT * FROM 
[LinkedServer].[Server].[Table] 
WHERE [TimeStamp]= (SELECT MAX(TimeStamp) 
FROM [LinkedServer].[Server].[Table] 
WHERE UserName IN 
(SELECT Tagname COLLATE DATABASE_DEFAULT FROM LocalServer.MyDatabase.dbo."Taglist" 
WHERE LOCATION = 'Europe' AND COUNTRY = 'England')) 

此查询工作正常，但是我想插入一个IF ELSE语句，所以如果我选择不同的日期，比MAX（时间戳）更大然后返回一个错误信息。我尝试的方式如下：

IF MAX(TimeStamp) > '2011-02-15' 
BEGIN 

SELECT * FROM 
[LinkedServer].[Server].[Table] 
WHERE [TimeStamp]= (SELECT MAX(TimeStamp) 
FROM [LinkedServer].[Server].[Table] 
WHERE UserName IN 
(SELECT Tagname COLLATE DATABASE_DEFAULT FROM LocalServer.MyDatabase.dbo."Taglist" 
WHERE LOCATION = 'Europe' AND COUNTRY = 'England')) 

END 
ELSE 
PRINT 'Date out of range' 

不幸的是，这种方式查询不起作用。关于我应该在哪里更改代码的任何建议？ 谢谢！

Answer 1

Declare @MaxTS datetime 

SELECT @MaxTS=MAX(TimeStamp) 
FROM [LinkedServer].[Server].[Table] 
WHERE UserName IN 
(SELECT Tagname COLLATE DATABASE_DEFAULT FROM LocalServer.MyDatabase.dbo."Taglist" 
WHERE LOCATION = 'Europe' AND COUNTRY = 'England') 

IF @MaxTS > '20110215' 
BEGIN 

SELECT * FROM 
[LinkedServer].[Server].[Table] 
WHERE [TimeStamp]= @MaxTS 

END 
ELSE 
PRINT 'Date out of range'