Current month data should up arrow when compare to previous month data not available in source file

[kaviyarasan]

Current Scenario:

Currently i'm taking month(o4) from Date (i.e 12.04.2019).but problem is i couldn't able to get month if data available in  the source.

case 1: Up Arrow

if current month > Prev Month

case 2: Down Arrow

if current month < Prev Month

Expected output:

case 3: Up Arrow

current month should show up arrow if prev month data is not available in source file

[Channa]

can you share your current expression..

try if(isnull(currentMonth),up,down)