Help needed in creating a SQL statement containing four joins
I have done it myself.

select 
    userID 
from 
    UserCities
where 
    CityID IN (select CityID 
               from school sc, student st 
               where sc.SchoolID = st.SchoolID and StudentID = 382) 
    and userID IN (select userID 
                   from users 
                   where tagNumber = 4521) ;