WEEK_ISO scalar function
The WEEK_ISO function returns the week of the year of the argument as an integer value in the range 1-53.
The schema is SYSFUN.
-
expression
- An expression that returns a value of one of the following built-in data types: DATE, TIMESTAMP, or a valid character string representation of a date or timestamp that is not a CLOB. In a Unicode database, if a supplied argument is a graphic string, it is first converted to a character string before the function is executed.
The week starts with Monday and always includes 7 days. Week 1 is the first week of the year to contain a Thursday, which is equivalent to the first week containing January 4. It is therefore possible to have up to 3 days at the beginning of a year appear in the last week of the previous year. Conversely, up to 3 days at the end of a year may appear in the first week of the next year.
The result of the function is INTEGER. The result can be null; if the argument is null, the result is the null value.
Example
The following list shows examples
of the result of WEEK_ISO and DAYOFWEEK_ISO.
DATE WEEK_ISO DAYOFWEEK_ISO
---------- ----------- -------------
1997-12-28 52 7
1997-12-31 1 3
1998-01-01 1 4
1999-01-01 53 5
1999-01-04 1 1
1999-12-31 52 5
2000-01-01 52 6
2000-01-03 1 1