WEEKNUM Function

Derives the numeric value for the week within the year (1, 2, etc.). Input must be the output of the DATE function or a reference to a column containing Datetime values. The output of this function increments on Sunday.

Week 1 of the year is the week that contains January 1.

Note

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

Wrangle vs. SQL: This function is part of Wrangle, a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.

Note

Depending on the locale where the calculation of this function is performed, the maximum number of weeks in a year may be 52 or 53. It's possible that you could see different results in your browser, Trifacta Photon, and other running environments due to locale.

Basic Usage

Column reference example:

weeknum(MyDate)

Output: Returns the numeric week number values derived from the MyDate column.

Syntax and Arguments

weeknum(datetime_col)

Argument	Required?	Data Type	Description
datetime_col	Y	datetime	Name of column whose week number values are to be computed

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

datetime_col

Name of the column whose week number 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:WEEKNUM(DATE(2017,12,20)).

Usage Notes:

Required?	Data Type	Example Value
Yes	Datetime	myDate

Examples

Tip

For additional examples, see Common Tasks.

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.

Functions:

Item	Description
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.
WEEKNUM Function	Derives the numeric value for the week within the year (`1`, `2`, etc.). Input must be the output of the `DATE` function or a reference to a column containing Datetime values. The output of this function increments on Sunday.
DATEFORMAT Function	Formats a specified Datetime set of values according to the specified date format. Source values can be a reference to a column containing Datetime values.

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

Transformation:

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

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	WEEKDAY (myDate)
Parameter: New column name	'weekDayNum'

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

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	DATEFORMAT(myDate, 'EEEE')
Parameter: New column name	'weekDayNameFull'

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

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	DATEFORMAT(myDate, 'EEE')
Parameter: New column name	'weekDayNameShort'

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

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	WEEKNUM (myDate)
Parameter: New column name	'weekNum'

Results:

myDate	weekDayNum	weekDayNameFull	weekDayNameShort	weekNum
10/30/17	1	Monday	Mon	44
10/31/17	2	Tuesday	Tue	44
11/1/17	3	Wednesday	Wed	44
11/2/17	4	Thursday	Thu	44
11/3/17	5	Friday	Fri	44
11/4/17	6	Saturday	Sat	44
11/5/17	7	Sunday	Sun	45
11/6/17	1	Monday	Mon	45

In this section: