Appending to a Pandas Dataframe From a pd.read_sql Output

How about

for i in orders: df = df.append(pd.read_sql(querystring, cnxn, params = [i]))

Need to assign the result:

df = df.append(pd.read_sql(querystring, cnxn, params = [i]))

you may try to do it this way:

df = pd.concat([pd.read_sql(querystring, cnxn, params = [i] for i in orders], ignore_index=True)

so you don't need an extra loop ...

alternatively if your orders list is relatively small, you can select all your rows "in one shot":

querystring = 'select order_number, creation_date from table_name where order_number in ({})'.format(','.join(['?']*len(orders)))

df = pd.read_sql(querystring, cnxn, params=orders)

generated SQL

In [8]: querystring
Out[8]: 'select order_number, creation_date from table_name where order_number in (?,?,?,?)'