C# 仅在C代码中出现SQL语法错误

我有以下代码：

"SELECT tblschemeprojectpaymentgateway.paymentgatewayid, paymentgatewayname FROM " + 
"tblschemeprojectpaymentgateway INNER JOIN tblpaymentgateway ON " +
"tblschemeprojectpaymentgateway.paymentgatewayid = tblpaymentgateway.paymentgatewayid"+
"WHERE tblschemeprojectpaymentgateway.schemeprojectid=`"+
SchemeProjectID.ToString()+"`", SqlConnection1);
sqlcmd.CommandType = CommandType.Text;

SqlConnection1.Open();

Npgsql.NpgsqlDataReader dr = sqlcmd.ExecuteReader();

它查询Postgresql数据库。SchemeProject是一个Guid。这段代码在pgAdmin数据库查询工具中执行良好，但在tblschemeprojectpaymentgateway周围的C代码中抛出语法错误

我已经在引号、backtics和原样中尝试了SchemeProjectID，有没有.ToString

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我想不出是怎么回事。

将字符串拆分成几行时出现的经典问题；您缺少tblpaymentgateway.paymentgatewayid和WHERE之间的空格。

您缺少WHERE前面第三行的空格

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为了避免在多行分割的字符串中丢失空格，我发现在字符串前面使用@符号可以从字面上理解多行字符串。例如：

string command = @"SELECT tblschemeprojectpaymentgateway.paymentgatewayid, paymentgatewayname FROM
                                tblschemeprojectpaymentgateway INNER JOIN tblpaymentgateway ON
                                tblschemeprojectpaymentgateway.paymentgatewayid = tblpaymentgateway.paymentgatewayid
                                WHERE tblschemeprojectpaymentgateway.schemeprojectid=`" + SchemeProjectID.ToString() + "`";

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此外，您可能需要研究语句的参数化，并可能将它们包装到存储过程中。

请公布确切的错误。共有4个tblschemeprojectpaymentgateway。错误在哪一个附近？也许“是错误的符号，一定是”

string command = @"SELECT tblschemeprojectpaymentgateway.paymentgatewayid, paymentgatewayname FROM
                                tblschemeprojectpaymentgateway INNER JOIN tblpaymentgateway ON
                                tblschemeprojectpaymentgateway.paymentgatewayid = tblpaymentgateway.paymentgatewayid
                                WHERE tblschemeprojectpaymentgateway.schemeprojectid=`" + SchemeProjectID.ToString() + "`";