Question

我有一个查询，它返回创建行的最新日期。日期是'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'))

这个查询工作正常，但我想插入一个IF ELSE语句，所以如果我选择一个不同的日期，大于MAX（TimeStamp）然后返回一条错误信息。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无效。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'

SQL：所选日期超出范围

1 个答案: