Generate a list in Power Query for each index value

[RolandsP]

Hi,

I have a simple table in Power Query.

It contains following columns:

- index (unique key for each table entry)

- revenue

- forecastIntervalMonths

- forecastStartDate

- forecastEndDate

From this, I need to generate a list of a forecasted revenue stream for each "index" value that starts at "forecastStartDate" and ends at or before "forecastEndDate". Revenue stream recurs at each interval "forecastIntervalMonths" which is given in number> of months. For example, if it is 3, it means that revenue repeats every three months. Revenue should equal "revenue" amount at each interval. Results should be included in one table.

I would highly appreciate if someone could share an idea how this could be accomplished.

Thanks,

Rolands

[MarcelBeug]

Maybe a question with a representative example would be a better idea than posting your question twice.

[RolandsP]

Here is how the data looks in a table:

I would like to have that new column is added which includes date list for each index value. For Index 1, it would include following dates (at 1-month interval) - 30/12/2017, 30/01/2018, 28/02/2018, 30/03/2018, ... 30/12/2019. 

Thanks!

[MarcelBeug · Accepted solution]

That would be something like this:

let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"index", Int64.Type}, {"revenue", Int64.Type}, {"forecastIntervalMonths", Int64.Type}, {"forecastStartDate", type date}, {"forecastEndDate", type date}}),
    AddedMonths = Table.AddColumn(#"Changed Type", "Months", each 12 * (Date.Year([forecastEndDate])-Date.Year([forecastStartDate])) + Date.Month([forecastEndDate]) - Date.Month([forecastStartDate]) - (if Date.Day([forecastStartDate]) > Date.Day([forecastEndDate]) then 1 else 0), Int64.Type),
    AddedDateList = Table.AddColumn(AddedMonths, "Dates", (ThisRow) => List.Transform({0..Number.IntegerDivide(ThisRow[Months],ThisRow[forecastIntervalMonths])}, each Date.AddMonths(ThisRow[forecastStartDate],_ * ThisRow[forecastIntervalMonths])), type {date}),
    RemovedMonths = Table.RemoveColumns(AddedDateList,{"Months"})
in
    RemovedMonths

[RolandsP]

This works exactly as I need. 

Thanks a lot!