How many papers are there?
select count(*) from papers
How many authors are there?
select count(*) from authors
How many of those papers are published by "Atsushi Ohori"?
select count(*) from authors as t1 join authorship as t2 on t1.authid = t2.authid join papers as t3 on t2.paperid = t3.paperid where t1.fname = "Atsushi" and t1.lname = "Ohori"