15.00 - WeekNumber_Of_Year - Teradata Database

WeekNumber_Of_Year

Purpose  

Returns the number of weeks from the beginning of the year to the specified date.

Syntax  

Syntax Elements

calendar_name

A calendar name. The possible values are Teradata, ISO, and COMPATIBLE.

This argument must be a character literal and cannot be a table column or expression. If you do not name a calendar, Teradata uses the calendar for the session.

expression

An expression that results in a DATE, TIMESTAMP, or TIMESTAMP WITH TIME ZONE value.

NULL

The business calendar for the session.

TD_SYSFNLIB

Name of the database where the function is located.

ANSI Compliance

This is a Teradata extension to the ANSI SQL:2011 standard.

Argument Types

The first argument, expression, is defined with the following data types:

DATE

TIMESTAMP

TIMESTAMP WITH TIME ZONE

The second argument, calendar_name, is optional and is defined with the following argument data types:

VARCHAR

NULL

If the argument passed to the function does not match one of these declared data types, an error is returned indicating that the function does not exist.

Result

The result is an INTEGER value from 0 through 53, where 1 is the first week of the year and 53 is the last week of the year. The value 0 means that there is a partial week in the year, Week0.

Usage Notes

The WeekNumber_Of_Year function provides improved performance compared to using the Sys_Calendar.Calendar system view to obtain similar results.

For more information about the CALENDAR system view, see Data Dictionary.

Example  

If the current date is January 5, 1901, the following query returns 0 because January 5, 1901, is in week 0 of 1901 in the Teradata calendar:

SELECT TD_SYSFNLIB.WEEKNUMBER_OF_YEAR (CURRENT_DATE);

The following query returns 1 because January 5, 1901, is in week 1 of 1901 in the COMPATIBLE calendar:

SELECT TD_SYSFNLIB.WEEKNUMBER_OF_YEAR (DATE ‘1901-01-05’, ‘COMPATIBLE’);