Derived Column based on Previous Value in Same

[RKM]

Dear Experts,

I have apparantly simple problem but finding it hard to resolve.

So, I got a table with 2 columns in Power BI as below.

Item ID----Session

A ----1

A ----2

B ----1

B ----4

B ----5

I need to find, how many Item arrived in a Session which was not in Previous Session. i.e.

Session ----New Item ----Comment
1 ----2 ----Both A & B
2 ----0 ----Nothing New, Since A was there on Session 1 already
3 ----0 ----Nothing
4 ----1 ----B - In this occasion B appeared in Session 4 but it was not there in Session 3
5 ----0 ----Nothing new, Since B was there on session 4 already

Now to achieve that basically what I am looking for is a "Derived Column" as below...

Item_ID	In_Session	Derived_IsNew
A	1	Y
A	2	N
B	1	Y
B	4	Y
B	5	N

Is this possible that way please? 

Another alternate hack someone suggested me is create another derived table etc. but if the above (Derived Column) idea is feasible then I dont want to go that way.

[amitchandak · Accepted solution]

@RKM , Try a new column like

new column =
var _cnt = countx(filter(Table, [In_Session] = earlier([In_Session]) -1 && [Item_ID] = earlier([Item_ID])), [Item_ID])
return
if( isblank(_cnt) , "Yes", "No")

[RKM]

Thanks a lot @amitchandak . Exactly what I wanted.