How many times has the student Linda Smith visited Subway?
SELECT count(*) FROM Student JOIN Visits_Restaurant ON Student.StuID = Visits_Restaurant.StuID JOIN Restaurant ON Visits_Restaurant.ResID = Restaurant.ResID WHERE Student.Fname = "Linda" AND Student.Lname = "Smith" AND Restaurant.ResName = "Subway";
counting visits refers to COUNT(*); student named Linda Smith refers to WHERE Fname = 'Linda' AND Lname = 'Smith'; visited Subway refers to Restaurant.ResName = 'Subway'; joining tables for comprehensive data refers to JOIN statements;