Calculate incremental quantity month by month

[mtrevisiol]

Hi everyone.

I've got this table which shows quantities entering and exiting the warehouse, month by month.

In the first row I have the initial stock of the first day of 2021 and I want to create the column "Running Qty" that calculates the resulting stock after entries and exits:

Item	Year	Month	Data	Initial stock	Qty	RunningQty
000BAGG000A12	2021	1	01/01/2021	2240	-20
000BAGG000A12	2021	2	01/02/2021	0	-20
000BAGG000A12	2021	3	01/03/2021	0	-70
000BAGG000A12	2021	4	01/04/2021	0	140
000BAGG000A12	2021	5	01/05/2021	0	-170
000BAGG000A12	2021	6	01/06/2021	0	-90
000BAGG000A12	2021	7	01/07/2021	0	-35
000BAGG000A12	2021	8	01/08/2021	0	0
000BAGG000A12	2021	9	01/09/2021	0	65
000BAGG000A12	2021	10	01/10/2021	0	-70
000BAGG000A12	2021	11	01/11/2021	0	-135
000BAGG000A12	2021	12	01/12/2021	0	-45
000BAGG000A12	2022	1	01/01/2022	0	-20
000BAGG000A12	2022	2	01/02/2022	0	-135
000BAGG000A12	2022	3	01/03/2022	0	-105
000BAGG000A12	2022	4	01/04/2022	0	-225
000BAGG000A12	2022	5	01/05/2022	0	-115
000BAGG000A12	2022	6	01/06/2022	0	135
000BAGG000A12	2022	7	01/07/2022	0	-125
000BAGG000A12	2022	8	01/08/2022	0	0
000BAGG000A12	2022	9	01/09/2022	0	0
000BAGG000A12	2022	10	01/10/2022	0	0
000BAGG000A12	2022	11	01/11/2022	0	0
000BAGG000A12	2022	12	01/12/2022	0	0

The ideal result would be:

I need to make a formula like:

IF (YEAR = 2021 & MONTH = 1, RunningQty = Initial Stock + Qty) 

ELSE Running Qty = Running Qty of the previous month + Qty of current month.

Here is the pbix file: https://www.dropbox.com/s/z6cwp0swofjwk1q/RunningQty.pbix?dl=0

Thank you for the help!

[amitchandak]

@mtrevisiol , A new measure

Sum(Table[Initial Stock]) + Sumx(filter(all(Table), [Item] = Max(Table[Item]) && [Date] <= Max(Table[Date]) ), Table[Qty] )

or

new column =
Table[Initial Stock] + Sumx(filter((Table), [Item] = earlier(Table[Item]) && [Date] <= earlier(Table[Date]) ), Table[Qty] )

[mtrevisiol]

I created the new column using your formula, but I didn't get what I needed..