c#将变量嵌入SQL语句中

最新推荐文章于 2025-05-20 00:30:00 发布

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最新推荐文章于 2025-05-20 00:30:00 发布 · 3.4k 阅读

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1、使用 ' " + + " ' 拼接

string mysql = 
    " SELECT Cname,Grade 
      FROM student,score,course 
      WHERE student.Sno = score.Sno and 
                  score.Cno = course.Cno and 
                  student.Sno = ‘" + Convert.ToString(textBox1.Text) + "’ and         
                  score.Text =‘" + Convert.ToInt32(comboBox1.Text) + “’;
    ”;

2、使用占位符

string mysql = string.Format(
    "SELECT Cname,Grade 
     FROM student,score,course 
     WHERE student.Sno = score.Sno and 
                score.Cno = course.Cno and 
                student.Sno = '{0}' and 
                score.Text = '{1}' " ,
    textbox1.Text,ComboBox1.Text);

String str="select zkzh,school,name,n1,fzf from yw01 where aaa= ' "+aaa+ " ' ";//字符串型变量
String str="select zkzh,school,name,n1,fzf from yw01 where aaa="+aaa;//int型变量

3、使用$符号