In my application I want to use MySQL with Google App Engine. I tried to search for solutions but didn't find an accurate answer. Some say its impossible to connect to MySQL, some say that Google Cloud SQL is one of the options.
Does anyone have ideas about the correct approach?
The capability to use MySQL within Google App Engine does exist via Google Cloud SQL. It works with both the Python and Java runtimes.
However, Google Cloud SQL is currently in limited preview. You can see details on how to enroll here.
While you wait to see if you get accepted into the preview, you can check out the instructions for Java and Python.