Update query is not working in ASP.Net

I am checking. I will get back to you soon.

lingers says:

Does spaces in mssql statement prevent it from working well

Yes. So use Trim function and use parameterized query.

Refer below modified code.

double yield1 = Convert.ToDouble(Session["qpr"]);
double yi1 = input1 / yield1;

string updateSQL;
updateSQL = "update stock set qtyprod = @qtyprod , lastprod = @lastprod, totalrev= @totalrev where no = @No and active ='1' ";

dbConn.ConnectionString = WebConfigurationManager.ConnectionStrings["DB_SCH"].ConnectionString;
cmd.Connection = dbConn;
cmd.CommandText = updateSQL;
cmd.CommandType = CommandType.Text;
cmd.Parameters.AddWithValue("@qtyprod", input1);
cmd.Parameters.AddWithValue("@lastprod", input1);
cmd.Parameters.AddWithValue("@totalrev", yi1);
cmd.Parameters.AddWithValue("@no", name.Trim());
try
{
    dbConn.Open();
    int updated = cmd.ExecuteNonQuery();
    dbConn.Close();
    if (updated == 1)
    {
        // Response.Redirect("changepassw.aspx");
    }
    else
    {
        // Label101.Text = "Process not Completed";
    }
}
catch (Exception err)
{
    Response.Write(err.ToString());
}
finally
{
    dbConn.Close();
}