Creating new column with merged values

[Orturcheh]

Hello dear community, 

I have a table of data with columns like Month, Sales, Team, etc..

What I need is to create a column, which will show:

For Month 01.2019  - Sum of Sales for monthNumber 1

For Month 02.2019 - Sum of Sales for monthNumber 1+2

For Month 03.2019 - Sum of Sales for monthNumber 1+2+3

and so on. 

I tried to create a new column using peek function, but it gave me strange figures.

This is a more complicated continuation of this question.

Thank you in advance for your help!

Sample data below.

[Channa]

Aggr(RangeSum(Above(Sum(Sales), 0, RowNo())), Month, (TASKNUMBER2, (NUMERIC)))

script

LOAD
date("Month",'MM.YYYY') as Month,
Area,
"Task Number" as TASK,
Division,
Team,

"Task Number" as TASKNUMBER,
AutoNumber("Task Number"&Team&Division&Area&Month) as TASKNUMBER2,
Sales
FROM [lib://TEST/RangeSum2.xlsx]
(ooxml, embedded labels, table is Sheet2);

[miskinmaz]

The as of table is quite easy with this kind of aggregation operation.

https://community.qlik.com/t5/Qlik-Design-Blog/The-As-Of-Table/ba-p/1466130