My Gmail account has multiple folders and labels. The iPad mail app can search through one of the folders. How can I search through all of it at once?
No way to do so on apple mail that I've seen, I've resorted to the cueup.com app (formerly called greplin) which has a search functionality that indexes all accounts you link to it, or cloudmagic as an alternative. it will pull up emails via search and open up the message on the browser (although you may have to mess with it if it keeps redirecting to gmail's mobile site). I'm sure one of these companies will be bought out by google or apple soon.