How to show number of user in online based on country wise ?

Description:
That is Possible to get number user online using status of that user. This website I have check the user is already login in the website or not. If not login then allow to login into the website and change his Status to "Y". If he click log out then we have update that user status "N".

How to update value "N" during browser close event?
We need to update database table value as "N" when user closed the browser I am using Global.asax file for update "N" value after session is expired.

How to calculate number of user online per country?
In this example site I have stored user details with country name. So when ever user login into the website I update status then show in the right side of the website number of available user per country. Like below code I count number of user

if (!Page.IsPostBack)
{
            if (Session["uname"] == null || Session["uname"].ToString() == "")
            {
                Response.Redirect("ErrorPage.aspx");
            }
            sqlcon.Open();
            sqlcmd = new SqlCommand("select distinct country from Login_Table", sqlcon);
            da = new SqlDataAdapter(sqlcmd);
            dt.Clear();
            da.Fill(dt);
            sqlcon.Close();
            if (dt.Rows.Count > 0)
            {
                sqlcon.Open();
                for (int i = 0; i <= dt.Rows.Count - 1; i++)
                {
                    sqlcmd1 = new SqlCommand("select count(*) from Login_Table where status='Y' and country='" + dt.Rows[i][0].ToString() + "'", sqlcon);
                    da1 = new SqlDataAdapter(sqlcmd1);
                    dt1.Clear();
                    da1.Fill(dt1);
                    if (dt1.Rows.Count > 0)
                    {
                        if (dt1.Rows[0][0].ToString() != "0")
                        {
                            Label1.Text += dt.Rows[i][0].ToString() + " " + dt1.Rows[0][0].ToString() + "
";
                        }
                    }
                }
                sqlcon.Close();
            }
}