Question

我的.Net应用程序中有以下SQL命令：

sqlCommand.Text = "DECLARE @method NVARCHAR(MAX);
                   SET @method = ' WITH selectRows AS (SELECT *, row=ROW_NUMBER() OVER(ORDER BY(SELECT 1)) FROM [' + @param + ']) SELECT ' + @param_2 + ' FROM selectRows WHERE row BETWEEN 0 AND 30;'
                   EXEC(@method);";
sqlCommand.Parameters.AddWithValue("@param", tableName);
sqlCommand.Parameters.AddWithValue("@param_2", columnString);

每当＆＃39; @ param_2＆＃39;很长时间查询不会执行。让我们说列字符串如下所示：

[class],[partnr],[accessoriesidentifier],[canbelinedup],[certificate],[certificate_ce],[certificate_ul],[certificate_vde],[codeletter],[construction],[craftcooling],[craftelectro],[craftfluid],[crafthydraulic],[craftlubrication],[craftmechanic],[craftpneumatic],[craftprocess],[create],[depth],[depthspacingfront],[depthspacingrear],[description1],[description2],[description3],[discount],[ecabinetmacro],[erpnr],[externaldocument1],[externaldocument2],[externaldocument3],[externalplacement],[functiongroup],[graphicmacro],[groupnumber],[groupsymbolmacro],[height],[heightspacingabove],[heightspacingbelow],[identcode],[identtype],[isaccessory],[lastchange],[lifetime],[macro3d],[maintenance],[manufacturer],[mountinglocation],[mountingspace],[note],[ordernr],[packagingprice1],[packagingprice2],[packagingquantity],[picturefile],[piecetype],[priceunit],[productgroup],[productsubgroup],[producttopgroup],[purchaseprice1],[purchaseprice2],[quantityunit],[reportid],[salesprice1],[salesprice2],[snapheight],[snapheightmiddleoffset],[spare],[stress],[supplier],[terminal],[typenr],[uniqueid],[usage],[wear],[weight],[width],[widthspacingleft],[widthspacingright],[barcount],[bardistance],[bargeometry],[barmountingplatedistance],[bottompaneldepth],[bottompaneldistance],[bottompanelprojectionback],[bottompanelprojectionfront],[bottompanelprojectionleft],[bottompanelprojectionright],[busbarholderpartnr],[busbarholdervariant],[busbarrailpartnr],[busbarrailvariant],[deliverylength],[dooroffsetright],[dooroffsettop],[doorthickness],[doortrabbet],[doortype],[hingeposition],[insertpointoffsetx],[profiledepth],[profiledistance],[profileheight],[rearpaneldistance],[rearpaneldpepth],[rearpanelprojectionbottom],[rearpanelprojectionleft],[rearpanelprojectionright],[rearpanelprojectiontop],[sidepaneldepth],[sidepaneldistance],[sidepanelprojectionback],[sidepanelprojectionbottom],[sidepanelprojectionfront],[sidepanelprojectiontop],[toppaneldistance],[toppaneldpepth],[toppanelprojectionback],[toppanelprojectionfront],[toppanelprojectionleft],[toppanelprojectionright],[vprofiledepth],[vprofilewidth],[wallthickness],[widthbottom],[widthtop],[variant],[adjustrange],[adressrange],[advancecontacts],[airgap],[assemblyspreaded],[awgfrom],[awgtill],[bendingradius],[cabledesignation],[cabledisplayform],[cablelength],[cabletype],[cableweight],[coding],[color],[connection],[connectioncrosssection],[connectiondesignation],[connectionmethod],[contactarrangement],[contacttype],[coppernumber],[creepagedistance],[crosssectionfrom],[crosssectiontill],[currentcsa],[currentiec],[currentul],[degofprotection],[design],[doordepth],[doorheight],[doormountingspace],[doorwidth],[electricalcurrent],[electricalpower],[firmwareversion],[flow],[holdingpower],[innerdiameter],[intrinsicsafety],[material],[norm],[outerdiameter],[paneldepth],[panelheight],[panelmountingspace],[panelwidth],[pincount],[pipeclass],[plcdeviceid],[plcisbuscoupler],[plcisbusdistributor],[plciscpu],[plcispowersupply],[plcobjectdescription],[plctype],[powerdissipation],[pressure],[pressurelevel],[shortcircuitresistant],[standardinvers],[strokelength],[symbolfile],[symbolnr],[technicalcharacteristics],[thread],[triggercurrent],[voltage],[voltagecsa],[voltageiec],[voltagetype],[voltageul],[widthrating],[wirecount],[wirecrosssection],[wirecrosssectionanddiameter],[wirecrosssectionunit],[variant_1],[characteristics],[connectiondescription],[connectiondesignation_1],[description],[functiondefcategory],[functiondefgroup],[functiondefid],[hasled],[hasplugadapter],[idx1],[idx2],[intrinsicsafety_1],[nesteddevicetag],[pos],[safetyrelevant],[symbol],[symbolmacro],[terminalfunction],[terminalnr],[partnr_1],[variant_2],[count],[parentvariant],[pos_1],[22235.0],[22236.0],[22237.0],[22238.0],[22239.0],[22240.0],[22241.0],[22196.1],[22196.2],[22158.1],[22158.2],[22159.1],[22159.2],[22195.1],[22195.2],[22228.1],[22228.2],[22228.3],[22228.4],[22228.5],[22228.6],[22228.7],[22228.8],[22228.9],[22228.10]

查询不会在服务器上执行（SQL Server 2005）。当我删除10列时，查询执行没有任何问题。我使用sql profiler查找sql server从我的应用程序收到的任何问题，但没有发现问题。我真的很困惑为什么它没有工作。

我尝试实现的是从数据库表中获取所有列的结果集而不使用行列。因为如果我将SELECT @ param_2更改为SELECT *，我将获得显示行号的所有列加上和额外的列。为了摆脱这个行号我想我只是将所有列名发送到查询的SELECT语句。但是我现在遇到了上述问题。我希望有人知道一个解决方案，要么解决上面的问题，要么如何获得所有列的结果集，排除行号以外的查询比我使用的更好。

P.s：（＆＃39;失败的＆＃39;）列字符串的大小为3612个字符。我对SQL本身没有太多经验。如果我犯了愚蠢的错误，请原谅。

编辑：列名取决于用户，因此无法在查询中对其进行硬编码。

Answer 1

也许这不会直接回答这个问题，但无论如何它可能会有所帮助。为什么你需要使用dynamioc sql？你为什么不能用这个：

string sql = @"
WITH CTE AS 
( 
         SELECT   *, 
                  row=Row_number() OVER (ORDER BY (SELECT 1)) 
         FROM     dbo.TableName 
SELECT [class],[partnr],[accessoriesidentifier],[canbelinedup],[certificate],[certificate_ce],[certificate_ul],[certificate_vde],[codeletter],[construction],[craftcooling],[craftelectro],[craftfluid],[crafthydraulic],[craftlubrication],[craftmechanic],[craftpneumatic],[craftprocess],[create],[depth],[depthspacingfront],[depthspacingrear],[description1],[description2],[description3],[discount],[ecabinetmacro],[erpnr],[externaldocument1],[externaldocument2],[externaldocument3],[externalplacement],[functiongroup],[graphicmacro],[groupnumber],[groupsymbolmacro],[height],[heightspacingabove],[heightspacingbelow],[identcode],[identtype],[isaccessory],[lastchange],[lifetime],[macro3d],[maintenance],[manufacturer],[mountinglocation],[mountingspace],[note],[ordernr],[packagingprice1],[packagingprice2],[packagingquantity],[picturefile],[piecetype],[priceunit],[productgroup],[productsubgroup],[producttopgroup],[purchaseprice1],[purchaseprice2],[quantityunit],[reportid],[salesprice1],[salesprice2],[snapheight],[snapheightmiddleoffset],[spare],[stress],[supplier],[terminal],[typenr],[uniqueid],[usage],[wear],[weight],[width],[widthspacingleft],[widthspacingright],[barcount],[bardistance],[bargeometry],[barmountingplatedistance],[bottompaneldepth],[bottompaneldistance],[bottompanelprojectionback],[bottompanelprojectionfront],[bottompanelprojectionleft],[bottompanelprojectionright],[busbarholderpartnr],[busbarholdervariant],[busbarrailpartnr],[busbarrailvariant],[deliverylength],[dooroffsetright],[dooroffsettop],[doorthickness],[doortrabbet],[doortype],[hingeposition],[insertpointoffsetx],[profiledepth],[profiledistance],[profileheight],[rearpaneldistance],[rearpaneldpepth],[rearpanelprojectionbottom],[rearpanelprojectionleft],[rearpanelprojectionright],[rearpanelprojectiontop],[sidepaneldepth],[sidepaneldistance],[sidepanelprojectionback],[sidepanelprojectionbottom],[sidepanelprojectionfront],[sidepanelprojectiontop],[toppaneldistance],[toppaneldpepth],[toppanelprojectionback],[toppanelprojectionfront],[toppanelprojectionleft],[toppanelprojectionright],[vprofiledepth],[vprofilewidth],[wallthickness],[widthbottom],[widthtop],[variant],[adjustrange],[adressrange],[advancecontacts],[airgap],[assemblyspreaded],[awgfrom],[awgtill],[bendingradius],[cabledesignation],[cabledisplayform],[cablelength],[cabletype],[cableweight],[coding],[color],[connection],[connectioncrosssection],[connectiondesignation],[connectionmethod],[contactarrangement],[contacttype],[coppernumber],[creepagedistance],[crosssectionfrom],[crosssectiontill],[currentcsa],[currentiec],[currentul],[degofprotection],[design],[doordepth],[doorheight],[doormountingspace],[doorwidth],[electricalcurrent],[electricalpower],[firmwareversion],[flow],[holdingpower],[innerdiameter],[intrinsicsafety],[material],[norm],[outerdiameter],[paneldepth],[panelheight],[panelmountingspace],[panelwidth],[pincount],[pipeclass],[plcdeviceid],[plcisbuscoupler],[plcisbusdistributor],[plciscpu],[plcispowersupply],[plcobjectdescription],[plctype],[powerdissipation],[pressure],[pressurelevel],[shortcircuitresistant],[standardinvers],[strokelength],[symbolfile],[symbolnr],[technicalcharacteristics],[thread],[triggercurrent],[voltage],[voltagecsa],[voltageiec],[voltagetype],[voltageul],[widthrating],[wirecount],[wirecrosssection],[wirecrosssectionanddiameter],[wirecrosssectionunit],[variant_1],[characteristics],[connectiondescription],[connectiondesignation_1],[description],[functiondefcategory],[functiondefgroup],[functiondefid],[hasled],[hasplugadapter],[idx1],[idx2],[intrinsicsafety_1],[nesteddevicetag],[pos],[safetyrelevant],[symbol],[symbolmacro],[terminalfunction],[terminalnr],[partnr_1],[variant_2],[count],[parentvariant],[pos_1],[22235.0],[22236.0],[22237.0],[22238.0],[22239.0],[22240.0],[22241.0],[22196.1],[22196.2],[22158.1],[22158.2],[22159.1],[22159.2],[22195.1],[22195.2],[22228.1],[22228.2],[22228.3],[22228.4],[22228.5],[22228.6],[22228.7],[22228.8],[22228.9],[22228.10]
FROM   CTE
WHERE  row BETWEEN @StartRow AND  @EndRow;";

using(var sqlCommand = new SqlCommand(sql, con))
{
    sqlCommand.Parameters.Add("@StartRow", SqlDbType.int).Value = 1; 
    sqlCommand.Parameters.Add("@EndRow", SqlDbType.int).Value = 30;
    // ...
}

由于列名是由用户指定的，因此如果没有动态sql，则无法将它们添加为参数。但是你知道所有有效的列名，所以你可以检查它们是否都有效。如果您不知道表格的所有列，请查看here并使用reader.GetSchemaTable在应用程序启动时加载所有列。

然后你可以简单地将它添加到sql：

string sql = @"
WITH CTE AS 
( 
         SELECT   *, 
                  row=Row_number() OVER (ORDER BY (SELECT 1)) 
         FROM     dbo.TableName 
SELECT {0}
FROM   CTE
WHERE  row BETWEEN @StartRow AND  @EndRow;";

sql = string.Format(sql, string.Join(",", columnList));

Answer 2

您的字符串文字和传递的参数本身都不是nvarchar(max)类型。因此，你对这句关于string concatenation：

的评论不屑一顾

如果字符串串联的结果超出了8,000字节的限制，则结果将被截断。但是，如果连接的字符串中至少有一个是大值类型，则不会发生截断。

我可能会做的是将参数更改为显式为nvarchar(max)：

sqlCommand.Parameters.Add("@param_2", SqlDbType.NVarChar,-1).Value =
     columnString;

或者您可以使用以下方法修复它：

SET @method = CONVERT(nvarchar(max),
' WITH selectRows AS (SELECT *, row=ROW_NUMBER() OVER(ORDER BY(SELECT 1)) FROM [') + ...

C＃SQL参数限制？

2 个答案: