Please help. Given a studentID and a TagNumber i want to get the UserID related to that TagNumber. The difficult condition is that TagNumbers can be duplicate within a Users table. So we can pinpoint the exact UserID using the UserCities table as a student is linked to a school and a school is linked to a city and UserCities table have linking information for users and cities. You can assume that the given studentID:45 and TagNumber:99.
I have tried this so far:
select u.UserID from UserCities uc inner join School sc on uc.CityID = sc.CityID inner join Student st on sc.SchoolID = st.SchoolID where st.StudentID = 9