How to get first record updated then send email problem

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C#3.5

Hi guys i have problem

this code send email based on timer every 5 minutes

it working ok but my problem i need to determine first rcord updated not inserted

and send email this is starting work

this is my code

timer1_Tick

Sales.SalesClass SalesClass1 = new Sales.SalesClass();
DataTable dt = SalesClass1.ShowSalesData("Data Source=192.168.1.5;Initial Catalog=Altawi-last06-01-2015;User ID=admin;Password=123");
dataGridView1.DataSource = dt;
dataGridView1.Refresh();
------
namespace Sales
{
class SalesClass
{
public DataTable ShowSalesData(string ConnectionString)
{
SqlConnection con = new SqlConnection(ConnectionString);
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandType = CommandType.Text;
cmd.CommandText = "showsales1";
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
DataSet ds = new DataSet();
da.Fill(ds);
DataTable dt = ds.Tables[0];
return dt;
}
}
}
}

SELECT     ROW_NUMBER() OVER (ORDER BY dbo.[Jeddah-Live$Sales Header].No_) AS [م], dbo.[Jeddah-Live$Sales Line].[Document No_] AS 'رقم الطلب', 
dbo.[Jeddah-Live$Sales Header].[Bill-to Name] AS 'العميل', dbo.[Jeddah-Live$Sales Line].Area AS 'نوع الصبه', dbo.[Jeddah-Live$Sales Line].Description AS 'البيان', 
dbo.[Jeddah-Live$Sales Header].[Pump No_] AS 'المضخه', CAST(ROUND(dbo.[Jeddah-Live$Sales Line].Quantity, 0, 1) AS int) AS 'المطلوب', 
CAST(ROUND(dbo.[Jeddah-Live$Sales Line].[Quantity Shipped], 0, 1) AS int) AS 'المصبوب', CAST(ROUND(dbo.[Jeddah-Live$Sales Line].[Outstanding Quantity], 0, 
1) AS int) AS 'المتبقى '
FROM         dbo.[Jeddah-Live$Sales Header] INNER JOIN
                      dbo.[Jeddah-Live$Sales Line] ON dbo.[Jeddah-Live$Sales Header].No_ = dbo.[Jeddah-Live$Sales Line].[Document No_] AND 
                      dbo.[Jeddah-Live$Sales Header].[Sell-to Customer No_] = dbo.[Jeddah-Live$Sales Line].[Sell-to Customer No_]

------------
The code above not have any problem and working
When first record updated send email

Example to show

orderno   quantity  shipped quantity

12            20               0

13            30               0

14            25               0

15           22                0

suppose order no 14 shipped quantity updated be 10 (meaning 0 be 10

then send email with starting work

after this any updated to any record not send

no problem i dont need any send email code but how to get record updated first