For each product, find first month of volume, start plot from that month onwards

[dapperscavenger]

Hello,

I'm looking for a way to compare product launches. I have a dataset of few hundred products, with sales volumes by month.

I want to find a way to show the first month each one sold as "month 1", etc.  That way I can compare trends for new product launches in the past.

For example, product A first sold in January, product B first sold in March:

Product	volume	Date	Month
A	100	January	1
A	80	February	2
A	75	March	3
A	40	April	4
B	100	March	1
B	90	April	2
B	95	June	3
B	100	July	4

In this way I can plot the product volumes from the date of first volume, even though they sold at different times:

What would be the best way to go about getting the end result?

[amitchandak · Accepted solution]

@dapperscavenger , Create a new column like

new column =
var _first = eomonth(minx(filter(table,[Product] = earlier([Product])),[Date]),0)
return
datediff(_first, eomonth([date],0), month)

[dapperscavenger]

Worked like a charm, thank you!