Based on the documentation in http://docs.grafana.org/reference/annotations/, I was under the assumption that neither MySQL nor PostgreSQL support annotation queries. That page has a list of backends supporting annotations, and MySQL is not on the list. Annotations are also not mentioned anywhere at http://docs.grafana.org/features/datasources/mysql/. However, when specifically looking for this feature, I found
https://github.com/grafana/grafana/commit/73cb0352312fb35d26b03088eb7cba1b38e8d982. This sounds very much like annotations are supported with MySQL.
Before I start building a schema and filling a database with test data, it would be great to know what the actual situation is now – is that commit outdated by now, or is the documentation incomplete?
(I had to make some URLs above not links or it would not let me submit this post.)