Calculate Aggregations Based on Conditions

Hi Sisense Community,

I am attempting to create a column chart that shows the count of users that have logged into our product in a given month, and then along side that, show the amount of users that logged in for the first time that month. 

For example: 

Month	# of Users	# of New Users	# of Existing Users
January 2023	15	5	10
February 2023	10	2	8

I have 3 fields that I'm using:

• Date of Session
• Date of First Session
• User_ID

I would like to group by the month of "date of session" and then have a value that looks to see if the month of "date of first session" is equal to the month  of "date of session" and then count the unique number of users where this condition is satisfied. 

I've been trying to use the IF or CASE functions, but I continue to get an error. I attached screenshots of the two methods I have tried. Any help would be greatly appreciated!

Thanks!

Lucas