Question

我正在使用MS SQL通过链接服务器查询iHistorian。我想循环SQL表中的不同标记名。我遇到的问题是将参数添加到ihistorian查询中。代码如下。我没有在标记名中包含声明，因为此时它不相关。

    SELECT timestamp AS Interval, Left(Right(TagName,Len(TagName)-5),Len(TagName)-10) as TagName,
CONVERT(decimal(10, 3), ROUND(value, 3)) As Value, quality 
FROM 
   OPENQUERY(IHISTORIAN,'
                SET starttime =''yesterday '', endtime =''yesterday +1h''  
                SELECT timestamp, tagname, value, ihRawData.quality 
                FROM ihRawData
                WHERE tagname = '+ @tagname +' 
                AND timestamp BETWEEN ''timestamp'' and ''timestamp'' 
                AND SamplingMode =Calculated
                AND CalculationMode =Average
                AND IntervalMilliseconds =1h
                ORDER BY tagname, timestamp')
                end

我遇到的问题是WHERE tagname = '+ @tagname +'点。该查询不喜欢'+ @tagname +'。它强调了第一个+，并说预期会有)。

我基本上想要独立于历史记录查询设置标记名，如前所述。

完整查询 -

use Optimiser_Test;

declare @tagname varchar(32)
--declare @rowcount int
--declare @maxrows int
--select @maxrows = count(*) from OptimiserTags

--set @rowcount = 0

set @tagname = 'UMIS.99FE1100.F_CV'

--while @rowcount < @maxrows
begin


SELECT timestamp AS Interval, Left(Right(TagName,Len(TagName)-5),Len(TagName)-10) as TagName,
CONVERT(decimal(10, 3), ROUND(value, 3)) As Value, quality 
FROM 
   OPENQUERY(IHISTORIAN,'
                SET starttime =''yesterday '', endtime =''yesterday +1h''  
                SELECT timestamp, tagname, value, ihRawData.quality 
                FROM ihRawData
                WHERE tagname = REPLACE(@tagName, '''','')
                AND timestamp BETWEEN ''timestamp'' and ''timestamp'' 
                AND SamplingMode =Calculated
                AND CalculationMode =Average
                AND IntervalMilliseconds =1h
                ORDER BY tagname, timestamp')
                end

NEW UPDATE -

use Optimiser_Test;


declare @tagname varchar(32)
declare @fullquery varchar(1000)

set @fullquery = 'SELECT timestamp AS Interval, Left(Right(TagName,Len(TagName)-5),Len(TagName)-10) as TagName,
CONVERT(decimal(10, 3), ROUND(value, 3)) As Value, quality 
FROM 
   OPENQUERY(IHISTORIAN,
                SET starttime =''yesterday '', endtime =''yesterday +1h''  
                SELECT timestamp, tagname, value, ihRawData.quality 
                FROM ihRawData
                WHERE tagname = '''+ @tagname +'''
                AND timestamp BETWEEN ''timestamp'' and ''timestamp'' 
                AND SamplingMode =Calculated
                AND CalculationMode =Average
                AND IntervalMilliseconds =1h
                ORDER BY tagname, timestamp'''''

begin
set @tagname = 'UMIS.99FE1100.F_CV'
exec (@fullquery)

end

新更新2 -

如果我使用查询中指定的标记名运行查询，如下所示，我得到以下结果。这是正确的。

use Optimiser_Test;

SELECT timestamp AS Interval, Left(Right(TagName,Len(TagName)-5),Len(TagName)-10) as TagName,
CONVERT(decimal(10, 3), ROUND(value, 3)) As Value, quality 
FROM 
   OPENQUERY(IHISTORIAN,'
                SET starttime =''yesterday '', endtime =''yesterday +1h''  
                SELECT timestamp, tagname, value, ihRawData.quality 
                FROM ihRawData
                WHERE tagname = UMIS.99FE1100.F_CV
                AND timestamp BETWEEN ''timestamp'' and ''timestamp'' 
                AND SamplingMode =Calculated
                AND CalculationMode =Average
                AND IntervalMilliseconds =1h
                ORDER BY tagname, timestamp')

结果

enter image description here

经过与James S的多次来回和与我的同事的进一步合作之后，我得到了回报我需要的东西。

Declare @SQLString varchar(1000)
Declare @TAGS VarChar(1000)

Set @Tags = '"UMIS.99FE1100.F_CV"'

SET @SQLString = 'SELECT timestamp AS Interval, Left(Right(TagName,Len(TagName)-5),Len(TagName)-10) as TagName,
CONVERT(decimal(10, 3), ROUND(value, 3)) As Value, quality 
FROM 
   OPENQUERY(IHISTORIAN,''
                SET starttime =''''yesterday '''', endtime =''''yesterday +1h'''',
                         SELECT timestamp, tagname, value, ihRawData.quality 
                FROM ihRawData
                WHERE tagname = ' + @Tags + '
                           and IntervalMilliseconds =1h,  
                           and CalculationMode =Average,
                           and SamplingMode =Calculated
                ORDER BY tagname, timestamp'')
                           '

Print @SQLString
Print @Tags
Exec (@SQLString)

Answer 1

你的问题是缺少@tagname周围的引号（假设它是一个字符串）但是我认为除了那个之外还有其他语法问题！

但是有没有理由使用OPENQUERY，而不是仅通过它的四个部分名称直接执行SQL引用源表：server.database.schema.table？

无论如何你应该换行：WHERE tagname = '+ @tagname +' ：WHERE tagname = '''+ @tagname +'''以修复现有查询。

这当然是假设@tagName不是用户输入的，否则你会对SQL注入攻击持开放态度。您可以使用REPLACE(@tagName, '''','')代替@tagName来解决此问题，但直接查询会更加安全......

直接查询示例：

SET starttime ='yesterday', endtime ='yesterday +1h'

SELECT timestamp AS Interval, 
       Left(Right(TagName,Len(TagName)-5),Len(TagName)-10) as TagName,
       CONVERT(decimal(10, 3), ROUND(value, 3)) As Value, 
       quality 
FROM IHISTORIAN.<dbname>.dbo.ihRawData
    WHERE tagname = @tagname 
        AND timestamp BETWEEN 'timestamp' and 'timestamp' 
        AND SamplingMode ='Calculated'
        AND CalculationMode ='Average'
        AND IntervalMilliseconds ='1h'
    ORDER BY tagname, timestamp

修改

更正了OPENQUERY示例:(但不确定行SET starttime =''yesterday '', endtime =''yesterday +1h''的用途是什么，所以这已被删除！）NB - 我假设SamplingMode，CalculationMode和IntervalMilliseconds应该是字符串，并将它们包含在转义引用中太。现在，整个SQL字符串首先构造成一个变量，然后再将其传递给OPENQUERY

use Optimiser_Test; declare @tagname varchar(32) DECLARE @startTimeStamp NVARCHAR(50), @endTimeStamp NVARCHAR(50) DECLARE @sql NVARCHAR(8000) --declare @rowcount int --declare @maxrows int --select @maxrows = count(*) from OptimiserTags --set @rowcount = 0 set @tagname = 'UMIS.99FE1100.F_CV' --while @rowcount < @maxrows begin SET @startTimeStamp = 'yesterday' SET @endTimeStamp = 'yesterday +1h' SET @sql = 'SELECT timestamp, tagname, value, ihRawData.quality FROM ihRawData WHERE tagname = ''' + REPLACE(@tagName, '''','') + ''' AND timestamp BETWEEN ''' + @startTimeStamp + ''' AND ''' + @endTimeStamp + ''' AND SamplingMode =''Calculated'' AND CalculationMode =''Average'' AND IntervalMilliseconds =''1h'' ORDER BY tagname, timestamp' SELECT timestamp AS Interval, Left(Right(TagName,Len(TagName)-5),Len(TagName)-10) as TagName, CONVERT(decimal(10, 3), ROUND(value, 3)) As Value, quality FROM OPENQUERY(IHISTORIAN, @sql) end

编辑2

好的 - 如果您的最终查询得到了您想要的内容，那么您需要做的就是声明一个NVARCHAR变量 - 用SQL填充它，然后将该变量传递给openQuery。我不认为你可以在函数调用的（）内动态构建字符串。

IE：

use Optimiser_Test; declare @tagname varchar(32) set @tagname = 'UMIS.99FE1100.F_CV' DECLARE @SQL NVARCHAR(4000) SET @SQL = 'SET starttime =''yesterday '', endtime =''yesterday +1h'' SELECT timestamp, tagname, value, ihRawData.quality FROM ihRawData WHERE tagname = ' + @tagname + ' AND timestamp BETWEEN ''timestamp'' and ''timestamp'' AND SamplingMode =Calculated AND CalculationMode =Average AND IntervalMilliseconds =1h ORDER BY tagname, timestamp' SELECT timestamp AS Interval, Left(Right(TagName,Len(TagName)-5),Len(TagName)-10) as TagName, CONVERT(decimal(10, 3), ROUND(value, 3)) As Value, quality FROM OPENQUERY(IHISTORIAN,@SQL)

查询iHistorian时使用SQL参数

1 个答案: