What does MAX(field_name) return when no data?

I have a scenario where a SELECT MAX() query may not have any results.

SELECT MAX(location_order) AS max_location_order
FROM locations_data
WHERE location_parent_id = '$new_location_insert_position_id'"

If there are no items with an appropriate location_parent_id value, what value does max_location_order take?
Null, 0 (zero) or unassigned?

hi...

if no data in the table... max(field_name) return the NULL value.

By
S.Ashokkumar
PDI
India.

Thank you for your reply.
What I mainly failed to ask is...
Is this behaviour the same in all reasonably current versions of MySQL?