WEEKNUM function
Date
The date as a sequential serial number.
ReturnType
A number which determines on which day the week begins. It also specifies how the weeks are numbered. If it is 21, ISO 8601 is followed, otherwise, the week containing January 1 is the first week of the year and gets assigned the number 1. If omitted, the parameter is assumed to be 1, meaning that weeks start on Sundays and that ISO 8601 is not followed. (Refer to the table for more information.)
Returns
The week number of the date (1 through 52).
Converts a date to a number representing the week number of the date.
The meaning of the return value varies depending on the
returnType parameter. To get a return value conforming to ISO
standards, either use the ISOWEEKNUM function or set the
parameter to 21. Refer to this table for more information:
| Value | Day week begins on |
|---|---|
| 1 (default) | Sunday |
| 2 | Monday |
| 11 | Monday |
| 12 | Tuesday |
| 13 | Wednesday |
| 14 | Thursday |
| 15 | Friday |
| 16 | Saturday |
| 17 | Sunday |
| 21 | Monday |