SQL selecting rows where one column's value is common across another criteria column

Question

I have a cross reference table that looks like this:

id  document_id  subject_id
1   8            21
2   5            17
3   5            76
4   7                    


        

Answer 1

select document_id from table1
 where subject_id in (17, 76)
 group by document_id
having count(distinct subject_id) = 2