i'm using the above mentioned function in a form. It should tell me the number of the week from a date, this date is set in a standard-date-field, so i use it in this way: weekofyear(name_of_the_date_field).
But it works only if in the date field a date is set from this year. I have some data-sets with a date from last year, and in these sets the function doesnt work? Why?