REST pages in a space resource empty when ordered by date on Oracle

Steps to reproduce:

Open /xwiki/rest/wikis/xwiki/spaces/Main/pages?order=date on an instance that uses Oracle as database

Expected result:

The result is non-empty.

Actual result:

The result is empty.

This is because the query matches on language = '' which is not working on Oracle because the empty string is stored as NULL.