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Function Reference
1010data Insights Platform offers a rich set of functions that may be used in value expressions when creating computed columns and in selection expressions when performing row selections.
Time/Date functions
The time/date functions are vector functions that operate on columns containing time-related data and return specific information about the date/time for each row.
Date Functions
These functions provide a set of tools for performing common and advanced operations on dates in the 1010data Insights Platform Macro Language.
prevwkday(X)
Returns the date of the last weekday on or before a date-related value.

Function Reference
1010data Insights Platform offers a rich set of functions that may be used in value expressions when creating computed columns and in selection expressions when performing row selections.
- All 1010data Functions
  1010data provides a whole range of functions that can provide information and act on your data.
- Time/Date functions
  The time/date functions are vector functions that operate on columns containing time-related data and return specific information about the date/time for each row.
  - Time functions
    These functions provide a set of tools for performing time-related operations in the 1010data Insights Platform Macro Language.
  - Date Functions
    These functions provide a set of tools for performing common and advanced operations on dates in the 1010data Insights Platform Macro Language.
    - date(X)
      Returns the date portion of a date+time value.
    - datetime(X;Y)
      Returns the date+time value corresponding to a given date and time.
    - day(X)
      Returns the day portion of a date-related value.
    - dayofwk(X)
      Returns the integer value corresponding to the day of the week of a date-related value.
    - dayofyr(P)
      Returns the integer value corresponding to the day of the year of a date-related value. (Available as of version 16.02)
    - days(X;Y)
      Returns the number of days between two date-related values.
    - dtunix(X;Y)
      Return a 1010 timestamp (date+time) value given an integer, bigint, or floating-point value representing Unix-epoch time. (Available as of version 18.04)
    - firstdate(X)
      Returns the date of the first day of the period specified by a date-related value.
    - fromdate(X;Y)
      Formats a date in the form YYYYMMDD as a string according to a template. (Available as of version 15.19)
    - fromdatetime(X;Y)
      Formats a date+time in the form XXXX.YYYYYYYYYYY as a string according to a template. (Available as of version 15.19)
    - gregor(X)
      Returns the date corresponding to the given number of days before the epoch (1/1/2035).
    - isodayofwk(X)
      Returns the ISO-8601 day of the week for a given date or timestamp. (Available as of version 16.04)
    - isoweek(X)
      Returns the ISO-8601 week-numbering week for a given date or timestamp. (Available as of version 16.04)
    - isoyear(X)
      Returns the ISO-8601 week-numbering year for a given date or timestamp. (Available as of version 16.04)
    - julian(X)
      Returns the number of days remaining until the epoch for a date-related value (using a similar convention to the Julian date).
    - lastdate(X)
      Returns the date of the last day of the period specified by a date-related value.
    - logindate(X)
      Returns the date of the current session's login within a given time zone.
    - logindatetime(X)
      Returns the date and time of the current session's login within a given time zone.
    - mkdate(Y;M;D)
      Make a date value from a year, month, and day. (Available as of version 20.04)
    - mkdatetime(Y;M;D;HH;MM;SS)
      Make a date+time (timestamp) value from year, month, day, hour, minute, and second numbers. (Available as of version 20.04)
    - mkdays(W;D;HH;MM;SS)
      Make a days (interval) value from weeks, days, hours, minutes, and seconds. (Available as of version 20.04)
    - mkmonths(Y;M)
      Make a months (interval) value from years and months. (Available as of version 20.04)
    - mktime(HH;MM;SS)
      Make a time value from hour, minute, and second numbers. (Available as of version 20.04)
    - mkyrmo(Y;M)
      Make a year+month value from a year and a month. (Available as of version 20.04)
    - mkyrqtr(Y;Q)
      Make a year+quarter value from a year and a quarter. (Available as of version 20.04)
    - month(X)
      Returns the month portion of a date-related value.
    - months(X;Y)
      Returns the number of months between two date-related values.
    - nextwkday(X)
      Returns the date of the first weekday on or after a date-related value.
    - periods(X;Y)
      Returns the number of days, months, quarters, or years between two date-related values, depending on the types of those values.
    - prevwkday(X)
      Returns the date of the last weekday on or before a date-related value.
    - quarter(X)
      Returns the quarter corresponding to a date-related value.
    - quarters(X;Y)
      Returns the number of quarters between two date-related values.
    - sdayofwk(X)
      Returns the text value corresponding to the day of the week of a date-related value.
    - shift(X;Y)
      Returns the date-related value shifted by the amount specified.
    - shiftmonths(X;Y;E)
      Returns the date-related value shifted by the number of months specified.
    - todate(X;Y)
      Convert a string, date+time, or date to a date value in the form YYYYMMDD. (Available as of version 15.19)
    - todatetime(X;Y)
      Convert a string, date+time, or date to a date+time value in the form XXXX.YYYYYYYYYYY. (Available as of version 15.19)
    - today(X;Y)
      Convert a string, date+time, or date to a date value in the form DD. (Available as of version 18.02)
    - todayname(X;Y)
      Convert a string, date+time, or date to the conventional name for the day of the week. (Available as of version 18.03)
    - todayofwk(X;Y)
      Convert a string, date+time, or date to a value corresponding to the day of the week. (Available as of version 18.02)
    - todayofyr(X;Y)
      Convert a string, date+time, or date to a value corresponding to the day of the year. (Available as of version 18.02)
    - todays(X;Y)
      Convert a string, months, or days value to a floating-point days interval. (Available as of version 15.19)
    - tomonth(X;Y)
      Convert a string, date+time, or date to a date value in the form MM. (Available as of version 18.02)
    - tomonthname(X;Y)
      Convert a string, date+time, or date to the conventional name for the month. (Available as of version 18.03)
    - tomonths(X;Y)
      Convert a string, days, or months value to an integer value representing the number of months. (Available as of version 15.19)
    - toquarter(X;Y)
      Convert a string, date+time, or date to an integer value in the form Q. (Available as of version 18.02)
    - toyear(X;Y)
      Convert a string, date+time, or date to an integer value in the form YYYY. (Available as of version 18.02)
    - toyrmo(X;Y)
      Convert a string, date+time, or date to a value in the form YYYYMM. (Available as of version 18.02)
    - toyrqtr(X;Y)
      Convert a string, date+time, or date to a value in the form YYYYQ. (Available as of version 18.02)
    - year(X)
      Returns the year portion of a date-related value.
    - years(X;Y)
      Returns the number of years between two date-related values.
    - yrmo(X)
      Returns the month form of a date-related value.
    - yrqtr(X)
      Returns the quarter form of a date-related value.
- Group functions (g_functions)
  Group functions, or g_functions, are used to perform operations, such as summarizations, on rows that have the same values in a set of given columns.
- Math functions
  Math functions are vector functions that perform mathematical operations on one or more columns and return a column of results based on the operation.
- Matrix functions
- Categorization functions
  Categorization functions are vector functions that organize data and determine logical groupings. These functions can be used for conditionalizing results and/or bucketing value ranges.
- String functions
  String functions are vector functions that manipulate vectors of strings to provide information about a string or substring, concatenate and split strings, or transform strings based on specified criteria.
- List functions
  List functions are scalar functions that return lists, subsets of lists, and combinations of lists, among other functionality. Lists, along with packages, are compound scalar data types that facilitate programmatic interaction with scalar data values and variables.
- Data-handling functions
  Data-handling functions are vector functions that return a hash value based on an input column or columns.
- Row functions
  Row functions are vector functions that return computational outputs for row inputs, as opposed to column outputs. Row inputs are defined as a space- or comma-separated list of column names.
- SQL compatibility functions
  SQL compatibility functions are functions that treat null values as SQL nulls.
- Financial functions
- System functions
  System functions are special functions in 1010data that return information about users, tables, and other system objects.
- Object functions
  The object functions can be used to check the existence, type, and accessibility of objects such as folders, tables, and queries on the 1010data Insights Platform.
- Miscellaneous functions
  This category of functions contains special functions that don't neatly fit into other categories of functions.

`prevwkday(X)`

Returns the date of the last weekday on or before a date-related value.

Syntax

prevwkday(X)

Input

Argument	Type	Description
`X`	any numeric type	A scalar value or the name of a column containing date-related values Valid values can be of the form: `date` `date+time`

For more information, see Dates and time.

Return Value

Returns the integer value (in date form) corresponding to the last weekday on or before the date-related value given as input.

Note: Weekdays are Monday through Friday, including holidays.

If the input values are not in one of the supported formats listed above, the function returns an erroneous or illogical output.

Example

In the Hourly U.S. Weather (1993) table (pub.demo.weather.hourly93), you can create a computed column that displays an integer value corresponding to the last weekday on or before the date value in the column named date:

<base table="pub.demo.weather.hourly93"/>
<willbe name="example" value="prevwkday(date)" label="Previous Weekday"/>
<colord cols="date,example"/>

For a date value of 06/16/93 (X=19930616), the result would be 06/16/93. (Since 6/16/93 is a Wednesday, which is a weekday, the same date is returned.)

For a date value of 01/24/93 (X=19930124), the result would be 01/22/93. (Since 1/24/93 is a Sunday, the date returned is the last weekday before, which is Friday, 1/22/93.)