Question

我的问题总是在抛出。请帮我找到问题。谢谢！

MySqlConnection cnn = new MySqlConnection(mysqladdress);

cnn.Open();

try
{
    MySqlCommand cmd = new MySqlCommand();
    cmd.Connection = cnn;
    cmd.CommandText = "SELECT * FROM info where StudentID ='" + textBox1.Text + "'and Name='" + textBox2.Text + "'";
    MySqlDataReader reader = cmd.ExecuteReader();

    int count = 0;
    while (reader.Read())
    {
        count = count + 1;
    }

    if (count == 1)
    {
        MessageBox.Show("Welcome");
    }
    else if (count > 1)
    {
        MessageBox.Show("Access Denied");
    }
    else
    {
        MessageBox.Show("Wrong student ID and Password");
    }

}
catch (Exception)
{
    throw;
}

Answer 1

这必须是一个错字或简单的东西，如果不知道确切的错误信息很难说清楚。

为避免此类错误，我建议您使用参数：

cmd.CommandText = "SELECT * FROM info where StudentID = @StudentID and Name= @Name";
cmd.Parameters.Add("@StudentID", SqlDbType.VarChar).Value = textBox1.Text;
cmd.Parameters.Add("@Name", SqlDbType.VarChar).Value = textBox2.Text;

'where子句'中的未知列“something”

1 个答案: