PowerBI Create List of Month Dates - powerbi

Question

Hi in powerbi I am trying to create a list of dates starting from a column in my table [COD], and then ending on a set date. Right now this is just looping through 60 months from the column start date [COD]. Can i specify an ending variable for it loop until?
List.Transform({0..60}, (x) =>
Date.AddMonths(
(Date.StartOfMonth([COD])), x))

Answer 1

Assuming
start=Date.StartOfMonth([COD]),
end = #date(2020,4,30),
One way is to add column, custom column with formula
= { Number.From(start) .. Number.From(end) }
then expand and convert to date format
or you could generate a list with List.Dates instead, and expand that
= List.Dates(start, Number.From(end) - Number.From(start)+1, #duration(1, 0, 0, 0))

Answer 2

Assuming you want start of month dates through June 2023. In the example below, I have 2023 and 6 hard coded, but this could easily come from a parameter Date.Year(DateParameter) or or column Date.Month([EndDate]).
Get the count of months with this:
12 * (2023 - Date.Year([COD]) )
+ (6 - Date.Month([COD]) )
+ 1
Then just use this column in your formula:
List.Transform({0..[Month count]-1}, (x) =>
Date.AddMonths(Date.StartOfMonth([COD]), x)
)
You could also combine it all into one harder to read formula:
List.Transform(
{0..
(12 * ( Date.Year(DateParameter) - Date.Year([COD]) )
+ ( Date.Month(DateParameter) - Date.Month([COD]) )
)
}, (x) => Date.AddMonths(Date.StartOfMonth([COD]), x)
)
If there is a chance that COD could be after the End Date, you would want to include error checking the the Month count formula.

Answer 3

Generate list:
let
Start = Date1
, End = Date2
, Mos = ElapsedMonths(End, Start) + 1
, Dates = List.Transform(List.Numbers(0,Mos), each Date.AddMonths(Start, _))
in
Dates
ElapsedMonths(D1, D2) function def:
(D1 as date, D2 as date) =>
let
DStart = if D1 < D2 then D1 else D2
, DEnd = if D1 < D2 then D2 else D1
, Elapsed = (12*(Date.Year(DEnd)-Date.Year(DStart))+(Date.Month(DEnd)-Date.Month(DStart)))
in
Elapsed
Of course, you can create a function rather than hard code startdate and enddate:
(StartDate as date, optional EndDate as date, optional Months as number)=>
let
Mos = if EndDate = null
then (if Months = null
then error Error.Record("Missing Parameter", "Specify either [EndDate] or [Months]", "Both are null")
else Months
)
else ElapsedMonths(StartDate, EndDate) + 1
, Dates = List.Transform(List.Numbers(0, Mos), each Date.AddMonths(StartDate, _))
in
Dates