use count set analysis to determine values on one getfieldselection not in value from another getfieldselections

[shawnqlikfv]

HELP!!! I have two separate date selection boxes ( PURCHASE_DATE1 and  PURCHASE_DATE2).

Given the Purchase Date selection below

PURCHASE_DATE1		Jan-16
PURCHASE_DATE2		Feb-16

I need to use set analysis expression to identify the count of customers from PURCHASE_DATE2 NOT on PURCHASE_DATE1.

In this case the result is 2 (customer DD and EE).

customer1	PURCHASE_DATE1		customer2	PURCHASE_DATE2
AA	Jan-16		AA	Feb-16
BB	Jan-16		BB	Feb-16
CC	Jan-16		CC	Feb-16
AA	Mar-16		DD	Feb-16
BB	Mar-16		EE	Feb-16
CC	Mar-16		FF	Mar-16