Often you only want to return the last X days of a query (e.g. last 30 days) and you want that to always be up to date (dynamic).
This snippet can be added to your WHERE clause to filter for the last X days:
SELECT <COL1>,...<COLN>, <DATE_COLUMN> FROM <TABLE> WHERE <DATE_COLUMN> > current_date - interval 'X' day
<COL1>,...<COLN>are all the columns you want to return in your query
<DATE_COLUMN>is your date column you want to filter on
Xis the number of days you want to filter on
For reference see Postgres’s date/time Functions and Operators.