Full date into month/year

You need to match a date table to a full date field, if in your transaction table you only have the month and year, you need to create a calculated column by adding day (01), so you can relate. Once related, you can use any of the columns in your date table to "group" in your chart. I'm going to pass a function that I use to create the date table, and the call I make on it. You can tailor it to your need.

let CreateDateTable = (StartDate as date, EndDate as date, optional Culture as nullable text) as table =>
let
DayCount = Duration.Days(Duration.From(EndDate - StartDate)),
Source = List.Dates(StartDate,DayCount,#duration(1,0,0,0)),
TableFromList = Table.FromList(Source, Splitter.SplitByNothing()),
ChangedType = Table.TransformColumnTypes(TableFromList,{{"Column1", type date}}),
RenamedColumns = Table.RenameColumns(ChangedType,{{"Column1", "Date"}}),
InsertYear = Table.AddColumn(RenamedColumns, "Year", each Date.Year([Date])),
InsertQuarter = Table.AddColumn(InsertYear, "QuarterOfYear", each Date.QuarterOfYear([Date])),
InsertMonth = Table.AddColumn(InsertQuarter, "MonthOfYear", each Date.Month([Date])),
InsertDay = Table.AddColumn(InsertMonth, "DayOfMonth", each Date.Day([Date])),
InsertDayInt = Table.AddColumn(InsertDay, "DateInt", each [Year] * 10000 + [MonthOfYear] * 100 + [DayOfMonth]),
InsertMonthName = Table.AddColumn(InsertDayInt, "MonthName", each Date.ToText([Date], "MMMM", "pt-BR"), type text),
InsertMonthNameENG = Table.AddColumn(InsertMonthName , "MonthNameENG", each Date.ToText([Date], "MMMM", "en-US"), type text),
InsertCalendarMonth = Table.AddColumn(InsertMonthNameENG, "MonthInCalendar", each (try(Text.Range([MonthName],0,3)) otherwise [MonthName]) & " " & Number.ToText([Year])),
InsertCalendarQtr = Table.AddColumn(InsertCalendarMonth, "QuarterInCalendar", each "Q" & Number.ToText([QuarterOfYear]) & " " & Number.ToText([Year])),
InsertDayWeek = Table.AddColumn(InsertCalendarQtr, "DayInWeek", each Date.DayOfWeek([Date])),
InsertDayName = Table.AddColumn(InsertDayWeek, "DayOfWeekName", each Date.ToText([Date], "dddd", Culture), type text),
#"InsertDay(3)" = Table.AddColumn(InsertDayName, "Day", each Date.ToText([Date], "ddd", "EN-us"), type text),
InsertDayNameENG = Table.AddColumn(#"InsertDay(3)", "DayOfWeekNameENG", each Date.ToText([Date], "dddd", "en-US"), type text),
InsertWeekStart = Table.AddColumn(InsertDayNameENG , "WeekStart", each Date.StartOfWeek([Date]), type date),
InsertWeekEnding = Table.AddColumn(InsertWeekStart , "WeekEnding", each Date.EndOfWeek([Date]), type date)
in
InsertWeekEnding
in
CreateDateTable

CALL

let
Source = fncCalendar(#date(Date.Year(Date.AddYears(DateTime.LocalNow(),-2)), Date.Month(DateTime.LocalNow()), Date.Day(DateTime.LocalNow())),

#date(Date.Year(DateTime.LocalNow()), Date.Month(DateTime.LocalNow()), Date.Day(Date.AddDays(DateTime.LocalNow(),1))), null),
#"Added Custom" = Table.AddColumn(Source, "Label", each Date.ToText(#date(Date.Year([Date]),Date.Month([Date]),Date.Day([Date])),"dd-MMM-yy"))
in
#"Added Custom"