View and advanced filtering

I want to make a view that shows all tasks that either
- have a due date before today, but are not completed
- have a start date or due date during the last 30 days before today or
during the next 30 days from today

As far as I understand I have to do it in the SQL tag, as the Advanced tag
does not seem to give opportunity for "OR" statements nor flexibility in
defining dates.

Does anybody have suggestions as to how the SQL should look like - or a
reference to where I can learn more about the OutlookSQL dialect?

Thankful for any suggestions.