如何从数据库中汇总数据的列数列在Varchar中我必须在Textbox2中显示结果 [英] How Can I Sum Vales Of Data From Database The Column Is In Varchar And I Have To Display Result In Textbox2

问题描述

Quote：

SqlConnection con = new SqlConnection（Data Source = SHANTANU \\SQLEXPRESS; Initial Catalog = ankur; Integrated Security =真正的）;



字符串查询=选择SUM（CAST（REPLACE（Net_Wt（）as int））FROM Packing WHERE Lot_No ='+ TextBox1.Text + ';



SqlCommand cmd = new SqlCommand（query，con）; //选择SUM（cast（marksobtained as int））作为'totalmarksobtained'from sampletab

con.Open（）;

SqlDataReader mydr;

mydr = cmd.ExecuteReader（）;

while（ mydr.Read（））

{

TextBox2.Text = mydr.ToString（）; // SUM（CAST（REPLACE（RunTime，'：'，'。' ）AS浮动））



}

con.Close（）;

SqlConnection con = new SqlConnection("Data Source=SHANTANU\\SQLEXPRESS;Initial Catalog=ankur;Integrated Security=True");

string query = "select SUM(CAST(REPLACE(Net_Wt() as int)) FROM Packing WHERE Lot_No='" + TextBox1.Text + "'";

SqlCommand cmd = new SqlCommand(query, con);//select SUM(cast(marksobtained as int)) as 'totalmarksobtained' from sampletab
con.Open();
SqlDataReader mydr;
mydr = cmd.ExecuteReader();
while (mydr.Read())
{
TextBox2.Text = mydr.ToString();//SUM(CAST(REPLACE(RunTime, ':','.') AS float))

}
con.Close();

获取错误就像你不能添加varchar值。并且无法转换为INT。

Getting Error like u cant add varchar values. and cant convert to INT.

推荐答案

更改

change

SUM(CAST(REPLACE(Net_Wt() as int)) 

to

to

SUM(convert(int, net_wt)) 

你不应该直接在sql查询中注入textbox1文本，因为存在风险sql注入，应该更改为参数化的sql，检查出来： parameterized-sql-or-give-me-death.html [ ^ ]

int value;
int.TryParse(TextBox1.Text, out value);

用查询中的值替换TextBox1.Text。



给它一个try.hope这会有所帮助。

replace TextBox1.Text with value in query.

Give it a try.hope this will help.

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