Users requested that I filter a list of announcements so that the logic would work like:
(Show All Users Notices OR Staff Notices) AND (Posted before today AND expire after today).
The default filtering doesn’t let you put the brackets into the filter query. Turns out that SharePoint runs the query in order and ‘virtually’ puts brackets around things.
So my eventual logic was(((Show all Users Notices Or Staff Notices) AND StartDate before Today) AND Expires After Today).