WORKDAY formula in Power BI

[Eagles83]

I want to count 3 business days from [dateX]   The result must exclude weekends and federal holidays. The Excel equivalent would be WORKDAY(dateX,3,'Federal Holiday Sheet'!A;A))  with the Federal Holiday Sheet listing all holiday dates in column A. So if dateX is 6/27/17 I want the result to be 6/30/17; if dateX is 6/30/17, I wante the result to be 6/6/17 (skip weekend and July4th).

[Funk-E-Guy]

The simplest way I found to calculate this without considering holidays (only weekends) is to use a SWITCH function on WEEKDAY of the date:

[Date] + SWITCH(WEEKDAY([Date]), 1, 3, 2, 3, 3, 3, 4, 5, 5, 5, 6, 5, 7, 4)

What this does is:

• Sun → Wed (+3)
• Mon → Thur (+3)
• Tue → Fri (+3)
• Wed → Next Mon (+5)
• Thur → Next Tue (+5)
• Fri → Next Wed (+5)
• Sat → Next Wed (+4)

[Anonymous]

I have been looking for a Formular equal to Excels <=WORKDAY(start_date, days, [holidays])>, maybe that would be the Solution:

// FnWorkingDays 
/*
@Startdate type DATE
@NumOfDays  type INT // negative counts back
@HDays     type Table, 
*/

let FnWorkingDays = (StartDate as date, NumOfDays as number, optional Holidays as table) as date =>
   
let
  // get Holidays from Table
  ListOfHolidays = if Holidays = null then {} else Table.Column(Holidays,"ColumnNameFromHolydayTable"),
  // Convert Dates into Numbers for Quiker Search
  NumListOfHolidays = List.Transform(ListOfHolidays ,each Number.From(_)),
  // Define the Direction of Count, Negativ: Backwards
  AddDayDirection = if NumOfDays<0 then -1 else 1,
  // make NumOfDays Absolute for Count
  NumOfDaysAbs = Number.Abs(NumOfDays),
  // generate a Datelist with to many dates
  GenerateListDates = List.Dates( StartDate, NumOfDaysAbs*3, #duration(1*AddDayDirection,0,0,0)),
  // Select all none Weendend dates
  ListDatesNoWeekend = List.Select(GenerateListDates,(_)=>Date.DayOfWeek(_, Day.Monday) < 5),
  // Select all none Holydaydates
  ListDatesNoHoliday = List.Select(ListDatesNoWeekend,(_)=>List.PositionOf(NumListOfHolidays,Number.From(_))=-1),
  // Pick the NumOfDays + 1 from list
  ListDates = List.LastN(List.FirstN(ListDatesNoHoliday,NumOfDaysAbs+1),1),
  // Output last Date
  outputDate = ListDates{0}
in
  outputDate
in
  FnWorkingDays

My first attempt was to Build the Func. with List.Generate(), couldn´t to work Proberly.

I expect this Function has a Overhead Problem with to Many Records, therefor please comment 

[tommuirwebb]

Hi Steven, this function works well unless the StartDate is a Monday and you attempt to subtract 1 business day from it - it then just returns the StartDate value instead of the last business day.

[v-yuezhe-msft · Accepted solution]

@Eagles83,

Firstly, import your Federal Holiday sheet and data table to Power BI Desktop.

Secondly, create a calendar table using calendar() function, create relationship between data  table and calendar table using date field, and create relationship between Federal Holiday table and calendar table using date field, here is an example for you.

Thirdly, create the following calculated columns in the calendar table.

WeekDay = WEEKDAY('Calendar'[Date])
Holiday = RELATED('Federal Holiday'[Holiday])
If work day = IF(OR('Calendar'[WeekDay]=1,'Calendar'[WeekDay]=7),0,IF(ISBLANK('Calendar'[Holiday]),1,0))
Rank = RANKX(FILTER('Calendar','Calendar'[If work day]=1),'Calendar'[Date],,ASC)
Add 3 businss days = LOOKUPVALUE('Calendar'[Date],'Calendar'[If work day],1,'Calendar'[Rank],'Calendar'[Rank]+3)

At last, create a calculated column using the following DAX in your data table.

Column = RELATED('Calendar'[Add 3 businss days])

Regards,

[Eagles83]

This was very helpful. Can you please clarify which 'Date' in your response represents my "DateX" in my question? I'm not sure if my DateX is the Date if the Fact Table for the Date in the Calendar table.

[Anonymous]

It's possible to calculate workdays without a Date table with the following Measure or Calculated Column in DAX:

Workdays Calculated =

    //the work days don't consider Saturdays and Sundays

    //calculate the number of days between the dates, and adds 1

    VAR numDays = DATEDIFF([Start Date], [End Date], DAY) + 1

    //verifies the week numbers of each date

    VAR weekNumStart = WEEKNUM([Start Date])

    VAR weekNumEnd = WEEKNUM([End Date])

    //calculates the number of weekends existing between dates

    VAR numWeekends = IF(

        weekNumStart <= weekNumEnd, //weeks in same year

        weekNumEnd - weekNumStart, //the difference is the number of weekends

        weekNumEnd - weekNumStart + 52 //if different years, adds the number of weeks in one year

    )

RETURN

    numDays - (numWeekends * 2) //calculates the number of days (*2 to remove Saturday and Sunday for each weekend)

[Eagles83]

I get an error at Step 3 saying Expression.Error: The name 'WEEKDAY' wasn't recognized. Make sure it's spelled correctly. 

Is WeekDay a dax formula or do I need to add a WeekDay table?