I'm currently using this to add post meta
add_post_meta($post_id, 'when', $date);
Naturally, it creates a new meta key/value combination each time.
I want to another value to the key, so that when date is submitted again, there are now TWO dates in the "when" meta key?
Would I then be able to query these dates? Or would storing them in the same meta key cause them to be unreadable later?
Eventually the goal is to count how many entries there are in the meta key, while still being able to process the dates as dates.
Is this possible or should a new method of storage be used?