Hey wierdtonic
I think I understand your issue. Due to the fact that these are start and enddates selecting a period works a bit differently for you (/your users) to get the needed result.
For example, if you want this period 01/01/2020 - 03/31/2020
You should set Start Date to <= 03/31/2020 and end_date to > 01/01/2020
If you convert your dates to int (03/31/2020 becomes 20200331) this will be a bit easier to do.
Another solution would be to join your table with a date-table. This is how we did it. Instructions found here
By joining this date-table with your table you will create a date for each day between start and end (if end is empty then now). This way your users can filter on this Day-field you created. This will select the right records from the database as long as at least one day is in that filtered period.
Hamza
