Extract year from date attribute

Hi András,
If your date attribute is called "my_date", you can write an expression like this:

my_date/@year

In the same way you can write my_date/@month or my_date/@day.
In general, this type of expression applies to all composite attributes. If you want the survey designer to suggest the possible field names, try to write a "wrong" expression an it will give you a hint like this: possible valid values in /sampling_point/my_date: [year, month, day]
Thanks,
Open Foris Team