How many visitors are there?
select count(*) from visitors
What is the Tourist_ID of the visitor whose detail is 'Vincent'?
select tourist_id from visitors where tourist_details = "Vincent"
Please show his visit date and detail.
select t2.visit_date, t2.visit_details from visitors as t1 join visits as t2 on t1.tourist_id = t2.tourist_id where t1.tourist_details = "Vincent"