Let's say we have a number of versions, and the version number is 1-10.
If we choose revert to this version in 7, then the 8,9,10 operation after 7 will be eliminated.
If you select revert changes from the this version in 7 then the 7 revision will be eliminated
If you select 7,8 revert changes from the This version then the changes made in both 7 and 82 versions will be eliminated
Update to revision and revert to revision are very similar, merging your local uncommitted modifications. The 2 differences are: Revert to revision will use this Rev as the latest version, and update to revision will not. So revert to revision is equivalent to first update to revision, then copy the content to other places, then update, and then overwrite the content back. So if you want to permanently revert to a previous version, use revert to revision if you just want to temporarily revert to a previous version, then use Update to revisionupdate to revision than revert to Revision to often see Tortoise SVN's right-click menu to know, there is update to revision, but there is no revert to revision.
Svn:revert to this version and revert changes the difference between this version