TimeSpan ts10 = new TimeSpan(10, 0, 0);
		TimeSpan ts1030 = new TimeSpan(10, 30, 0);
		TimeSpan ts11 = new TimeSpan(11, 0, 0);
		TimeSpan ts1130 = new TimeSpan(11, 30, 0);

		SqlConnection conUpdate = new SqlConnection("server=test;database=master;user id=user1;passsword=user@1");
		SqlCommand commandUpdate = new SqlCommand("update empattendencesheet set remarks@remarks", conUpdate);
		commandUpdate.Parameters.Add("@remarks", SqlDbType.Int).Value = 1;
		SqlConnection con = new SqlConnection("server=test;database=master;user id=user1;passsword=user@1");
		SqlCommand command = new SqlCommand("select empcode,empname,todaydate,signIn,signout,remarks from empattendencesheet", con);
		con.Open();
		conUpdate.Open();
		SqlDataReader dataRader = command.ExecuteReader();
		if (dataRader.HasRows)
			while (dataRader.Read())
			{
				TimeSpan ts = Convert.ToDateTime(dataRader["signIn"]).TimeOfDay;
				if (ts <= ts10)
					commandUpdate.Parameters["@remarks"].Value = 1;
				else if (ts <= ts1030)
					commandUpdate.Parameters["@remarks"].Value = 2;
				else if (ts <= ts11)
					commandUpdate.Parameters["@remarks"].Value = 3;
				else
					commandUpdate.Parameters["@remarks"].Value = 4;
				commandUpdate.ExecuteNonQuery();
			}
		con.Close();
		conUpdate.Close();

hi, below should help you

mark my both the replies as answered one