Power BI Create a Calendar table automatically
In our models, the best way to deals with dates and DAX intelligence functions is to use a Calendar Table (Dimension). Good news, this table can be created in 2 clicks with Power Query (Transform Data) in Power BI!
Go transform data and right click on Queries to create a new Blank Query
Copy / Paste this code
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", Culture), type text),
InsertCalendarMonth = Table.AddColumn(InsertMonthName, "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),
InsertWeekEnding = Table.AddColumn(InsertDayName, "WeekEnding", each Date.EndOfWeek([Date]), type date)
in
InsertWeekEnding
in
CreateDateTable
Choose a start date and an EndDate, click Invoke
That’s it! You have a beautiful calendar table.

Credit: I found this code on internet many years ago and used it in the LazyDAX file. I think I changed it, but I can’t redirect and credit the one who created it. I think it can help you a lot, that’s why I’m sharing it with you :)