How many students are there in the record?
select count(*) from students
What about those with address in Wisconsin?
select count(*) from addresses as t1 join students as t2 on t1.address_id = t2.address_id where t1.state_province_county = "Wisconsin"
Show me the first and last names of those students.
select t2.first_name, t2.last_name from addresses as t1 join students as t2 on t1.address_id = t2.address_id where t1.state_province_county = "Wisconsin"