What's draft number of the documents?
select draft_number from draft_copies;
How about the draft copies? Show me how many draft copies each document has?
select document_id, count(copy_number) from draft_copies group by document_id;
Which of the result has the most draft copies?
select document_id, count(copy_number) from draft_copies group by document_id order by count(copy_number) desc limit 1;