Export multiple queries to excel

Hi,
I've got a door_order table which I export to excel, now I have to make it so that underneath each door_order the products are listed from door_product table, please not that this can be more than one product for that order.

This is my code so far
public DataTable GetData(SqlCommand cmd)
{
DataTable dt = new DataTable();
SqlConnection con =
new SqlConnection(@"Data Source=;Initial Catalog=bargaindoors;Persist Security Info=True;User ID=;Password=");
SqlDataAdapter sda = new SqlDataAdapter();
cmd.CommandType = CommandType.Text;
cmd.Connection = con;
try
{
con.Open();
sda.SelectCommand = cmd;
sda.Fill(dt);
return dt;
}
catch (Exception ex)
{
throw ex;
}
finally
{
con.Close();
sda.Dispose();
con.Dispose();
}
}


protected void Calculate_Click(object sender, EventArgs e)
{
string startDate = testinput.Text;
string endDate = testinput2.Text;

string strQuery = "SELECT O_ID AS ID, O_Datecreated AS 'Date Created', O_Ath AS Ath, Amount, Delivery, CU_Title AS Title, CU_F_Name AS Name, CU_L_Name AS Surname, CU_Address1 AS Address1, CU_Address2 AS Address2, CU_City AS City, CU_County AS County, CU_Country AS Country, CU_Postal AS Postal, PO, '\"' + Instructions + '\"', O_ID AS products FROM door_order WHERE O_Ath='A' AND " +
"O_Datecreated BETWEEN '" + startDate + "' AND '" + endDate + "'";
SqlCommand cmd = new SqlCommand(strQuery);
//Response.Write(startDate);
DataTable dt = GetData(cmd);

string attachment = "attachment; filename=Enquiry.xls";
Response.ClearContent();
Response.AddHeader("content-disposition", attachment);
Response.ContentType = "application/vnd.ms-excel";
string tab = "";
foreach (DataColumn dc in dt.Columns)
{
Response.Write(tab + dc.ColumnName);
tab = "\t";
}
Response.Write("\n");
int i;
foreach (DataRow dr in dt.Rows)
{
tab = "";
for (i = 0; i < dt.Columns.Count; i++)
{
Response.Write(tab + dr.ToString());
tab = "\t";
}
Response.Write("\n");
}
Response.End();
}
}