# WEEKINTERVAL

Creates a date interval in weeks.

### Parameter List

Syntax
WEEKINTERVAL(startweekendweek
[startyear]
[endyear]
[weektype]
)
startweek

ISO week number where the interval should start. For example: 7.

endweek

ISO week number where the interval should end. For example: 14.

[optional] startyear

Year in which the interval should start. For example: 2020.

[optional] endyear

Year in which the interval should end. For example: 2021.

[optional] weektype

A number representing the day that a week starts on as well as the system used for determining the first week of the year. For example: 1 or 2.

• If 'type' is '1' or is omitted, days are counted from Sunday and the value of Sunday is 1, therefore the value of Saturday is 7. (System 1*)
• If 'type' is '2', days are counted from Monday and the value of Monday is 1, therefore the value of Sunday is 7. (System 1*)
• If 'type' is '11', days are counted from Monday and the value of Monday is 1, therefore the value of Sunday is 7. (System 1*)
• If 'type' is '12', days are counted from Tuesday and the value of Tuesday is 1, therefore the value of Monday is 7. (System 1*)
• If 'type' is '13', days are counted from Wednesday and the value of Wednesday is 1, therefore the value of Tuesday is 7. (System 1*)
• If 'type' is '14', days are counted from Thursday and the value of Thursday is 1, therefore the value of Wednesday is 7. (System 1*)
• If 'type' is '15', days are counted from Friday and the value of Friday is 1, therefore the value of Thursday is 7. (System 1*)
• If 'type' is '16', days are counted from Saturday and the value of Saturdau is 1, therefore the value of Friday is 7. (System 1*)
• If 'type' is '17', days are counted from Sunday and the value of Sunday is 1, therefore the value of Saturday is 7. (System 1*)
• If 'type' is '21', days are counted from Monday and the value of Monday is 1, therefore the value of Sunday is 7. (System 2) The difference between System 1 and System 2 ist that System 2 uses ISO 8601 standard and starts counting weeks from the first Thursday of the year, while System 1 starts counting from January 1st.

### Examples

WEEKINTERVAL(1, 10) returns [2021-12-26; 2022-03-05]