Those are the issues that database migrations try to prevent (such as Rails or Laravel do). However, Q2A doesn't support them.
As I personally like Git's diff very much, when trying to compare things I always try to use it -- it is console-based, clear enough and it doesn't depend on the operating system.
So this is what I would do:
- Install the Q2A version I'm interested in comparing my current installation to (I'm assuming v1.7.5, but any will do)
- Export the structure of the current installation to a current.sql file (only structure, no data!). Check this https://stackoverflow.com/questions/6175473
- Export the stucture of the just installed v1.7.5 in the same way to a default.sql file.
- In a new directory, setup the git repo with: git init
- Add and commit the current.sql file
- Remove the current.sql file
- Move the default.sql file to the directory
- Rename the default.sql file to current.sql file
- git diff
Steps from 4 to 9 just show a non-OS-dependent way of diff-ing files. You could use an IDE, in Windows there is the Winmerge tool, in Linux you could use just the diff command. Considering it is just a single file, you could even use online tools.
Anyway, whatever method you choose, you will be able to see what has changed from your current schema to the default one for a given version.