Mail can be sorted oldest to newest in Gmail by clicking on the email count and choosing Oldest. However, for search results, the sort order selections seem to be disabled:
Is it possible to sort search results in Gmail oldest to newest?
I checked in Advanced Search, too, but there's no sort order option there. Searching the web didn't get any decent info for me, it all seems to be about how to sort folders, not search results.
Best Answer
That option doesn't sort. When it is available it allows you to jump to the last page of search results.
I find that the option is valuable when the search is simple, you are getting all the messages with a label. Once you stray into more complex searches the message is 1-x of many, and you can't click one button to jump to the end.