Breakdown the YTD sales into monthly by item

[Anonymous]

Hi there

Can anyone help me to figure out the best way to calculate monthly sales per item if all I have is the Year to Date Sales which is cumulative? 

For example: Assuming the Year starts on Jan 21, so on Jan-21 the sales for Item A will be $10000, in Feb 21 the sales for Item A will be $500.

Period    Item Name    Year to Date Sales

Jan-21   A            $10,000.00

Jan-21   B            $2,000.00

Jan-21   C            $0.00

Jan-21   D            $500.00

Jan-21   E            $1,002.00

Jan-21   F            $999.00

Jan-21   G            $100.00

Jan-21   H            $150.00

Jan-21   I             $599.00

Jan-21   J             $3,092.00

Feb-21  A            $10,500.00

Feb-21  B            $2,500.00

Feb-21  C            $500.00

Feb-21  D            $1,000.00

Feb-21  E            $1,502.00

Feb-21  F            $1,499.00

Feb-21  G            $600.00

Feb-21  H            $650.00

Feb-21  I             $1,099.00

Feb-21  J             $3,592.00

[amitchandak · Accepted solution]

@Anonymous , Create date  column with help from month year

Date = Datevalue("01-"&[Period])

Then a new column

=

var _date = eomonth([Date],-1)

return

sumx(filter(Table, [Item Name] = earlier([Item Name])  && eomonth([Date],0) = _date) ,  [Year to Date Sales]) -[Year to Date Sales]