Site doesn't work now

about 10 days ago, my site was fine. Now the page loads only partially and when I try to log in, i get this message (below). My client doesn’t make edits much, so I’m sure I have outdated drupal. I’m not sure how to proceed to fix it – especially since I can’t access it!

Any ideas?

Recoverable fatal error: Argument 2 passed to SelectQuery::fields() must be of the type array, null given, called in /home/cc9028/public_html/includes/ on line 284 and defined in SelectQuery->fields() (line 1320 of /home/cc9028/public_html/includes/database/

Thank you for any input!