Using Sanity Studio I've created 2 documents in a simple schema "users" (the structure is not that important), and then updated each of them with some values, and published.
Trying to get the results using the query:
*[_type=="users"]
instead of getting 2 documents, I've got 4, and it seems each update created a new revision and all revisions of all documents were returned.
Is this how Sanity's edit works each time? If so, how do I just get the 2 documents with all the latest changes?
It sounds like you're probably getting both the published and the draft versions of each document. A draft will have the same _id as the published document but will be prepended with drafts..
This might be a bit clearer if you modify your query to the following, which will return an array of _ids:
*[_type=="users"]._id
If this is in fact what's happening, you can modify your query to exclude drafts:
*[_type=="users" && !(_id in path("drafts.**"))]
Here's a bit more detail about drafts.