// select query 의 단일 값
        int iCount = 0;

        using (SqlConnection con  = new SqlConnection("ConnectionString"))
        {
            //command
            SqlCommand cmd = new SqlCommand("select count(0) from dbo.test", con);
            cmd.CommandType = CommandType.Text;

            con.Open();

            // 쿼리의 단일값
            iCount = Convert.ToInt32(cmd.ExecuteScalar());
        }

        Response.Write(iCount.ToString());