This is half correct. MySQL is not available in Debian *STABLE*. It was allowed ...

RealSpamapS on April 25, 2018 | parent | context | favorite | on: One Giant Leap for SQL: MySQL 8.0 Released

This is half correct. MySQL is not available in Debian STABLE.

It was allowed to stay in unstable:

https://packages.debian.org/sid/mysql-server-5.5

However, the maintainers are uninterested in maintaining it there, since the release and security team have overrode them and forcibly removed it from stable.

kasabali on April 25, 2018 [–]

I know that but I didn't mention it because it would be an irrelevant detail in our context.