How many problems were reported on or before 1986-11-13?
select count(*) from problems where date_problem_reported <= "1986-11-13"
how about after?
select count(*) from problems where date_problem_reported > "1986-11-13"
Show me their problem ids and product ids!
select problem_id, product_id from problems where date_problem_reported > "1986-11-13"
For these, show the number of problems by product id!
select count(*), t2.product_id from problems as t1 join product as t2 on t1.product_id = t2.product_id where t1.date_problem_reported > "1986-11-13" group by t2.product_id