Q:

Not understanding this SQL query

I'm following the Stanford's Coursera database course, and there's this query I do not understand. 
The instructor says that it returns colleges paired with the highest GPA of their applicants. 
select distinct College.cName, state, GPA
from College, Apply, Student
where College.cName = Apply.cName
  and Apply.sID = Student.sID
  and GPA >= all
          (select GPA from Student, Apply
           where Student.sID = Apply.sID
             and Apply.cName = College.cName);

I don't understand the GPA >= all part.  Doesn't that mean we are looking for rows with GPA that is >= ALL applicants, instead of just applicants to a particular college?  In other words, I think the query is returning colleges that have applicants with GPA highest everywhere. 

A:

College.cName = Apply.cName

This provides the limit to a particular college.   Try removing it.