It creates a combined set of all the lists you provide. Duplicates in the new list will be removed.
If a value or list is not available:
UNION_OF_ANYsimply ignores it and combines what is available.
UNION, before returning a result, will ask users to go back and provide the missing list.
p is Person
A person in a case has lived in Germany, Switzerland, and Singapore. Being a fine, law abiding citizen, the person has not been banned from any countries.
[de, ch, sg]
UNION_OF_ANYis used, the request for ‘countries banned from’ is ignored, because there are none for this person.
Would you have used
UNIONinstead, the system would have alerted you to provide one or more countries the person is banned from before giving you the combined list.