oracle - SQL Query to fetch data from the last 30 days?

Question

Hi I am new to Oracle. How do I do a simple statement, for example get product id from the last 30, or 20 days purchase date?

SELECT productid FROM product
WHERE purchase_date ? 

question from:https://stackoverflow.com/questions/5210817/sql-query-to-fetch-data-from-the-last-30-days

Answer 1

SELECT productid FROM product WHERE purchase_date > sysdate-30