如何删除错误：必须声明标量变量 [英] how to remove error : must declare the scalar variable

问题描述

大家好，



我无法删除此错误，我也不知道为什么我会遇到这些错误。

我的代码块是：

 dt.OpenCon（）; 
 
 SqlCommand cmd = new SqlCommand（）; 
 
 cmd.Parameters.AddWithValue（@ DAY，DateTime.Today.Day）; 
 cmd.Parameters.AddWithValue（@ Month，DateTime.Today.Month）; 
 
 string str =SELECT MA_First_Name，MA_Email_Id FROM Master_Applicant WHERE DATEPART（DAY，MA_DOB）= @DAY AND DATEPART（MONTH，MA_DOB）= @Month; 
 DataSet ds = dt.ExecuteDataSet（str）; 

我想比较Day&表中出生日期的月份。



如何删除此错误。

解决方案

< pre lang =c＃> dt.OpenCon（）;
string str = SELECT MA_First_Name，MA_Email_Id来自Master_Applicant WHERE DATEPART（DAY，MA_DOB）= @DAY AND DATEPART（MONTH，MA_DOB）= @Month;
SqlCommand cmd = new SqlCommand（str）;
cmd.Parameters.AddWithValue（ @ DAY，DateTime.Today.Day）;
cmd.Parameters.AddWithValue（ @ Month，DateTime.Today.Month）;
DataSet ds = dt.ExecuteDataSet（cmd）;

我已经改变了添加参数和执行sql语句的顺序，首先用你的sql语句创建命令并为其添加参数。最后执行命令。

Hello all,

I am unable to remove this error also i don't know why i am facing these error.
My code block is:

dt.OpenCon();

        SqlCommand cmd = new SqlCommand();

        cmd.Parameters.AddWithValue("@DAY", DateTime.Today.Day);
        cmd.Parameters.AddWithValue("@Month", DateTime.Today.Month);
        
        string str = "SELECT MA_First_Name,MA_Email_Id FROM Master_Applicant WHERE DATEPART(DAY, MA_DOB) = @DAY AND DATEPART(MONTH, MA_DOB) = @Month";
        DataSet ds = dt.ExecuteDataSet(str);

I want to compare Day & month with the Date of birth in table.

How can i remove this error.

解决方案

dt.OpenCon();
string str = "SELECT MA_First_Name,MA_Email_Id FROM Master_Applicant WHERE DATEPART(DAY, MA_DOB) = @DAY AND DATEPART(MONTH, MA_DOB) = @Month";
SqlCommand cmd = new SqlCommand(str);
cmd.Parameters.AddWithValue("@DAY", DateTime.Today.Day);
cmd.Parameters.AddWithValue("@Month", DateTime.Today.Month);
DataSet ds = dt.ExecuteDataSet(cmd);

I have change the sequence of adding parameters and executing sql statement, first create the command with your sql statement and add parameters to it. finally execute the command.

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