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You can upload, test the query and if it's not working as intended, delete it via menu -> Admin -> Queries -> List Queries. Make your changes and upload/activate the query again. Test, rinse, repeat 
The web front end will also take care of exporting the query result to Excel, JSON, XML, CSV, HTML etc for you. Just look for the buttons on the right side of the menu bar (near the 'Search Attributes' box).
And don't forget - you can always post to the forums and ask for help!
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