def insert_billing(df):
        df = df.where((pd.notnull(df)), None)
        for row in df.to_dict(orient="records"):
            bill_item = row['Bill.Item']
            bill_qty = row['Billed Qty']
            bill_doct_date = row['Billi.Doc.Date']
            bill_doc = row['Billing Doc.']
            bill_net_value = row['Billi.Net Value']
            sales_order = row['Sales Order']
            import_date = DT.datetime.now().strftime('%Y-%m-%d')
            query = "INSERT INTO sap_billing(" \
                    "bill_item, " \
                    "bill_qty, " \
                    "bill_doc_date, " \
                    "bill_doc, " \
                    "bill_net_value, " \
                    "sales_order, " \
                    "import_date" \
                    ") VALUES (" \
                    "\"{}\", \"{}\", \"{}\", \"{}\"," \
                    "\"{}\", \"{}\", \"{}\"" \
                    ") ON DUPLICATE KEY UPDATE " \
                    "bill_qty = VALUES(bill_qty), " \
                    "bill_doc_date = VALUES(bill_doc_date), " \
                    "bill_net_value = VALUES(bill_net_value), " \
                    "import_date = VALUES(import_date) " \
                    "".format(
                        bill_item,
                        bill_qty,
                        bill_doct_date,
                        bill_doc,
                        bill_net_value,
                        sales_order,
                        import_date
            query = query.replace('\"None\"', 'NULL')
            query = query.replace('(None', '(NULL')
            query = query.replace('\"NaT\"', 'NULL')
            query = query.replace('(NaT', '(NULL')
                q1 = gesdb_connection.execute(query)
            except Exception as e:
                print(bill_item, bill_doc, sales_order, e)
    if __name__ == "__main__":
        engine_str = 'mysql+mysqlconnector://root:abc123@localhost/mydb'
        file_name = "tmp/dataload/so_tracking.XLSX"
        df = pd.read_excel(file_name)
        if df.shape[1] == 35 and compare_columns(list(df.columns.values)) == 1:
            insert_billing(df)
        else:
            print("Incorrect column count, column order or column headers.\n")

import pandas as pd
df = pd.DataFrame({'Sales Order': [1217252835, 1217988754, 1219068439], 
                   'Billing Doc.': [3222102723, 3209781889, 3214305818]})
   Billing Doc.  Sales Order
0    3222102723   1217252835
1    3209781889   1217988754
2    3214305818   1219068439

 file_name = "tmp/dataload/so_tracking.XLSX"
    df = pd.read_excel(file_name)
    print(df['Billing Doc.'])
680    3.252170e+09
681    3.252170e+09
682    3.252170e+09
683    3.252170e+09
684    3.252170e+09
685    3.252170e+09
686    3.252170e+09
687    3.252170e+09
688    3.252170e+09
689    3.252170e+09
690    3.252170e+09
694    3.251601e+09
695    3.251631e+09
696    3.252013e+09
697             NaN
698    3.252272e+09
699    3.252360e+09
700    3.252474e+09
Name: Billing Doc., dtype: float64