WEEKDAY Function

Derives the numeric value for the day of the week (1, 2, etc.). Input must be a reference to a column containing Datetime values.

NOTE: If the source Datetime value does not include a valid input for this function, a missing value is returned.

Tip: You can use the DATEFORMAT function to generate text versions of the day of the week. See Examples below.

Basic Usage

Column reference example:

derive type:single value:WEEKDAY(MyDate)

Output: Generates a column of values containing the numeric weekday values derived from the MyDate column.

Syntax

derive type:single value:WEEKDAY(datetime_col)

ArgumentRequired?Data TypeDescription
datetime_colYdatetimeName of column whose weekday values are to be computed

For more information on syntax standards, see Language Documentation Syntax Notes.

datetime_col

Name of the column whose day-of-week value is to be computed.

  • Missing values for this function in the source data result in missing values in the output.
  • Multiple columns and wildcards are not supported.

Tip: You cannot insert constant Datetime values as inputs to this function. However, you can use the following: WEEKDAY(DATE(12,20,2017)).

Usage Notes:

Required?Data TypeExample Value
YesDatetimemyDate

Examples

Example - Day of Date functions

This example illustrates how you can apply functions to derive day-of-week values out of a column of Datetime type:

  • WEEKDAY - returns numeric value for the day of the week for source Datetime values. See WEEKDAY Function.
  • WEEKNUM - returns the numeric value for the week within the year for source Datetime values. See WEEKNUM Function.
  • DATEFORMAT - can be used to format Datetime values in many different ways. See DATEFORMAT Function.

Source:

myDate
10/30/17
10/31/17
11/1/17
11/2/17
11/3/17
11/4/17
11/5/17
11/6/17


Transform:

The following generates a numeric value for the day of week in a new column:

derive type:single value: WEEKDAY (myDate) as:'weekDayNum'

The following generates a full text version of the name of the day of the week:

derive type:single value:DATEFORMAT(myDate, 'EEEE') as:'weekDayNameFull'

The following generates a three-letter abbreviation for the name of the day of the week:

derive type:single value:DATEFORMAT(myDate, 'EEE') as:'weekDayNameShort'

The following generates the numeric value of the week within the year:

derive type:single value: WEEKNUM (myDate) as:'weekNum'

Results:

myDateweekDayNumweekDayNameFullweekDayNameShortweekNum
10/30/171MondayMon44
10/31/172TuesdayTue44
11/1/173WednesdayWed44
11/2/174ThursdayThu44
11/3/175FridayFri44
11/4/176SaturdaySat44
11/5/177SundaySun45
11/6/171MondayMon45

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