How many times did Linda Smith visit a restaurant?
select count(*) from student join visits_restaurant on student.stuid = visits_restaurant.stuid where student.fname = "Linda" and student.lname = "Smith";
For those visits, how long did she spend?
select sum(spent) from student join visits_restaurant on student.stuid = visits_restaurant.stuid where student.fname = "Linda" and student.lname = "Smith";