You can do this but not directly in AppGini in its current state.
Your provider most likely has phpmyAdmin setup and you can export a database in many formats or just the data. Depending on how often you wish to do this doing it in phpmyAdmin or some other app is very easy. I use Navicat and it works for me.
Now if you are doing this very often (once a day or more) then a built in function would make it easier but I cannot figure out an instance where you would need to do this very often. It really comes down to usage and frequency. You can also take the csv data output from phpmyAdmin (as an example) and bring it into excel then have an excel macro sort the columns as you wish.
But you could built it yourself using fputcsv and then write some code which shows you the field names and you could put a 1, 2, etc beside them in a box and then have your code use the ranking to determine the output/sort order. You could have this appear at the bottom of the Members page.
See this link:
http://php.net/manual/en/function.fputcsv.php
Let this list know how often you would need this functionality. It would not be hard to add this into pageViewMembers.php found in the admin folder. As there are a limited # of fields in the members table I most likely would write the code to run a function which displays a field list, and as above, you put numbers beside them to state the output order.
I just tested doing this with Navicat, exported the data with field titles, opened in Excel, re-arranged the columns and it took less than 2 minutes.
Another question I would have is do you need this done by someone who does not have admin access but needs that data?
I know this does not answer your question directly but the answers may help in deciding if such a function is needed or is really a specialized function that may not be used by enough to warrant building it in.
Darn, while writing this I think I have figured it all out. But no time to test/write the code.
Alan