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.
注記
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.
注記
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.
ヒント
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
ヒント
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 ( |
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 three-letter 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 |