I think I have checked this through but it appears that the advanced search does not allow one to search for a date array i.e. in the same manner as one can search for items.
What I would like to be able to do is to output items by date(s) or range of dates and also to have the option of items arranged in date (or alphabetic) order.
Seems to be a simple matter of adding the right php code to the advanced search form. That is if you know enough php - I don't! Perhaps someone very kind soul could provide the necessary code?
I would also love to hear more on this, perhaps have a page in the codex on how to sort items by date?
I'm not sure how to search by a range of dates, but if you wanted a browse page sorted by date you could do that by a linked url. For example a link from the primary nav like this
<?php echo public_nav(array('Browse Items' => uri('items'), 'Browse Collections'=>uri('collections'), 'By Date'=>uri('items?sortby=dc.date&sortorder=asc'))); ?>
Where 'By Date' links to a page that sorts items by dublin core date in ascending order.
Actually the code above is incorrect.
John Flatness corrected this to:
'By Date' => ('/items?sort_field=Dublin Core,Date'),
Ascending sort is the default, so you can leave sort_dir out.