gistfile1.txt

from datetime import date, timedelta

start_date = date(2016, 5, 17)
stop_date = date(2019, 9, 30)

date_to_process = start_date

while date_to_process <= stop_date:

    print(f"""
    delete from notification_history 
    where created_at <= '{date_to_process}';
    """)
    date_to_process = date_to_process + timedelta(days=1)



Output:

    delete from notification_history
    where created_at <= '2016-05-17';


    delete from notification_history
    where created_at <= '2016-05-18';

.....
....

    delete from notification_history
    where created_at <= '2019-09-29';


    delete from notification_history
    where created_at <= '2019-09-30';