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 dayofweek values out of a column of Datetime type.
Functions:
Item  Description 

WEEKDAY Function  Derives the numeric value for the day of the week ( 
WEEKNUM Function  Derives the numeric value for the week within the year ( 
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 


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 


Parameter: Formula type  Single row formula 
Parameter: Formula  DATEFORMAT(myDate, 'EEEE') 
Parameter: New column name  'weekDayNameFull' 
The following step generates a threeletter abbreviation for the name of the day of the week:
Transformation Name 


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 


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 