This webinar discussed how to create a date dimension in Power BI and the best practices for using them. We enjoyed sharing this webinar with our audience and have included a few presentation resources.

Below is the M function we used for our Calendar table:

//Date function (put in blank query in M):

Source = (StartDate as date, EndDate as date, optional Culture as nullable text) as table =>

Source = List.Dates(StartDate, DayCount, #duration(1, 0, 0, 0)),
DayCount = Duration.Days(Duration.From(EndDate - StartDate))+1,
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]),type text),
InsertQuarterNum = Table.AddColumn(InsertYear, "Quarter Num", each Date.QuarterOfYear([Date])),
InsertQuarter = Table.AddColumn(InsertQuarterNum, "Quarter", each "Q" & Number.ToText([Quarter Num])),
InsertMonth = Table.AddColumn(InsertQuarter, "Month Num", each Date.Month([Date]), type text),
InsertStartOfMonth = Table.AddColumn(InsertMonth, "StartOfMonth", each Date.StartOfMonth([Date]), type date),
InsertEndOfMonth = Table.AddColumn(InsertStartOfMonth, "EndOfMonth", each Date.EndOfMonth([Date]), type date),
InsertDay = Table.AddColumn(InsertEndOfMonth, "DayOfMonth", each Date.Day([Date])),
InsertDayInt = Table.AddColumn(InsertDay, "DateInt", each [Year]*10000 + [Month Num]*100 + [DayOfMonth]),
InsertMonthName = Table.AddColumn(InsertDayInt, "Month", each Date.ToText([Date], "MMMM", Culture), type text),
InsertShortMonthName = Table.AddColumn(InsertMonthName, "Month short", each Date.ToText([Date], "MMM", Culture), type text),
InsertCalendarMonth = Table.AddColumn(InsertShortMonthName, "Month Year", each [Month]& " " & Number.ToText([Year]),type text),
InsertCalendarQtr = Table.AddColumn(InsertCalendarMonth, "Quarter Year", each "Q" & Number.ToText([Quarter Num]) & " " & Number.ToText([Year]), type text),
InsertDayWeek = Table.AddColumn(InsertCalendarQtr, "Weekday Num", each Date.DayOfWeek([Date])),
InsertDayName = Table.AddColumn(InsertDayWeek, "Weekday", each Date.ToText([Date], "dddd", Culture), type text),
InsertShortDayName = Table.AddColumn(InsertDayName, "Weekday short", each Date.ToText([Date], "ddd", Culture), type text),
InsertWeekEnding = Table.AddColumn(InsertShortDayName , "EndOfWeek", each Date.EndOfWeek([Date]), type date),
InsertWeekNumber= Table.AddColumn(InsertWeekEnding, "Week Num", each Date.WeekOfYear([Date])),
InsertMonthWeekNumber= Table.AddColumn(InsertWeekNumber, "WeekOfMonth Num", each Date.WeekOfMonth([Date])),
InsertYearMonthNumber = Table.AddColumn(InsertMonthWeekNumber,"YearMonth Num", each [Year]*100 + [Month Num]),
TypeChanges = Table.TransformColumnTypes(InsertYearMonthNumber,{{"YearMonth Num", Int64.Type},{"Week Num", Int64.Type},{"WeekOfMonth Num", Int64.Type},{"Quarter", type text},{"Year", type text}, {"DateInt", Int64.Type}, {"DayOfMonth", Int64.Type}, {"Month Num", Int64.Type}, {"Quarter Num", Int64.Type}, {"Weekday Num", Int64.Type}})


And our M code we used to ‘call’ the M function is here:

//Date function query (put in blank query in M, currently set to go to end of year for current day):
Source = DateQuery(#date(2019, 1, 1), 
DateTime.Date(  DateTime.LocalNow()  )),

If you have any questions, please reach out to our team or learn about our Business Intelligence services here.