I happened to be talking about this with a couple of friends just moments ago. Their opinion basically amounted to this:

* MySQL is a really awful database. It's usable only for small hobby projects, like a simple Wordpress site or so. For serious datasets, it's a horror. Complex queries on large amounts of data are just broken. Many features don't work or work incorrectly. The design is fundamentally flawed.

* Use PostgreSQL instead.

* If you absolutely have to use MySQL, use MariaDB instead. It's a fork that fixed some of the issues.

* Still better use PostgreSQL. Or even Oracle or SQL Server. They're fine, MySQL is not.