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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.

注意

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

提示

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

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

Basic Usage

Column reference example:

weekday(MyDate)

Output: Returns the numeric weekday values derived from the MyDate column.

Syntax and Arguments

weekday(datetime_col)

Argument

Required?

Data Type

Description

datetime_col

Y

datetime

Name 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.

提示

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 Type

Example Value

Yes

Datetime

myDate

Examples

提示

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