Table1 
     |     sno     |        Product name     |        dec     |        QTY     |        Unit_Price     |        Tax     |        Total_Amount     |        Tax_Amount     |        Grand_Total_Amount     |      |   
     |     1     |        mobile     |        no     |        2     |        5000     |        10     |        10000     |        1050     |        11550     |      |   
     |     2     |        ABC     |        no     |        1     |        500     |        10     |        500     |        1050             |        11500     |      |   
     |     0     |      |      |      |      |      |      |        1050     |        11550     |      |   
 
     Table2
       |     sno     |        Product name     |        dec     |        QTY     |        Unit_Price     |        Tax     |        Total_Amount     |        Tax_Amount     |        Grand_Total_Amount     |      |   
     |     1     |        mobile     |        no     |        2     |        5000     |        10     |        10000     |        1000     |        11000     |      |   
     |     2     |        ABC     |        no     |        1     |        500     |        10     |        500     |        50     |        550     |      |   
     |     0     |        0     |        0     |        0     |        0     |        0     |        10500     |        1050     |        11550     |      |   
 
    My Records Save like Table1
   And I am want to save records table 2
   How to do.....???
       
// Insert data in Grid view
private void addbutton_Click(object sender, EventArgs e)
{
if (producttxt.Text != "" && dectxt.Text != "" && qtytxtprice.Text != "" && txtqty.Text != "" && txttax.Text != "")
{
int Qty = Convert.ToInt32(txtqty.Text);
   decimal Unit_Price = Convert.ToDecimal(qtytxtprice.Text);
   decimal Tax = Convert.ToDecimal(txttax.Text);
   decimal Amount = (Qty * Unit_Price);
   decimal PercentageAmount = ((Amount * Tax) / 100);
   decimal TotalAmount = Amount + PercentageAmount;
     int Sno = dataGridView.Rows.Count ;
                              dataGridView.Rows.Add(Sno, producttxt.Text, dectxt.Text, txtqty.Text, qtytxtprice.Text, txttax.Text, TotalAmount);
                              btnclr_Click(sender, e);
                              CalculateTotalAmount();
                              ClearData();
                          }
                      }
             public void CalculateTotalAmount()
{
   decimal taxtotal=0;    
   decimal totalamount=0;    
   for(int i=0;i<dataGridView.Rows.Count-1;i++)    
                      {
   decimal TotalAmount = (Convert.ToDecimal(dataGridView.Rows[i].Cells[3].Value) * Convert.ToDecimal(dataGridView.Rows[i].Cells[4].Value));  
                      taxtotal=taxtotal+((Convert.ToDecimal(dataGridView.Rows[i].Cells[5].Value)*TotalAmount)/100);    
                      totalamount=totalamount+Convert.ToDecimal(dataGridView.Rows[i].Cells[6].Value);    
                      }    
                      TotalTaxtxt.Text=taxtotal.ToString(); //tax total amount text box field value setting    
                      totalamounttxt.Text=totalamount.ToString(); //total amount text box field value setting    
                      }
    // Insert records in databse
   private void btn_Insert_Click(object sender, EventArgs e)
          {
     int Billno = billno("Select ISNULL(Max(Billno+1),1) From MainBillForm");
     foreach (DataGridViewRow g1 in dataGridView.Rows)
              {
     SqlCommand cmd = new SqlCommand("insert into MainBillForm (Billno,Name,Mobile_no,Date,Order_Number,Sno,Product_Name,Description,Qty,Unit_Price,Tax,Amount,Tax_Amount,Total_Amount) Values ('" + Billno + "','" + Nametxt.Text + "','" + Phtxt.Text + "','" + dateTimePicker1.Value + "','" + ONtxt.Text + "','" + g1.Cells[0].FormattedValue.ToString() + "','" + g1.Cells[1].FormattedValue.ToString() + "','" + g1.Cells[2].FormattedValue.ToString() + "','" + g1.Cells[3].FormattedValue.ToString() + "','" + g1.Cells[4].FormattedValue.ToString() + "','" + g1.Cells[5].FormattedValue.ToString() + "','" + g1.Cells[6].FormattedValue.ToString() + "','" + TotalTaxtxt.Text + "','" + totalamounttxt.Text + "')", con);
                  con.Open();
                  cmd.ExecuteNonQuery();
   MessageBox.Show("Records Inserted SuccessFully");
   this.Hide();
   MainBillfrm sd = new MainBillfrm();
   sd.Show();
   con.Close();
                }
                }