Something more on the exists function on the same lines:
If you want to do the distinct load on a field we can use:
Load A, B, C, from Employees.csv where not exists (A);
This is equivalent to performing a distinct load on field A.
Read about this in the help file for exists function it will help you in clearing your concepts about exists function, also do understand on how Qlik stores data internally in form of bit stuffed pointers.